lguest: PAE support
This version requires that host and guest have the same PAE status. NX cap is not offered to the guest, yet. Signed-off-by: Matias Zabaljauregui <zabaljauregui@gmail.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
This commit is contained in:
Matias Zabaljauregui
Rusty Russell
parent
cefcad1773
commit
acdd0b6292
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@ -37,7 +37,6 @@ Running Lguest:
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"Paravirtualized guest support" = Y
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"Lguest guest support" = Y
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"High Memory Support" = off/4GB
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"PAE (Physical Address Extension) Support" = N
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"Alignment value to which kernel should be aligned" = 0x100000
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(CONFIG_PARAVIRT=y, CONFIG_LGUEST_GUEST=y, CONFIG_HIGHMEM64G=n and
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CONFIG_PHYSICAL_ALIGN=0x100000)
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@ -17,8 +17,13 @@
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/* Pages for switcher itself, then two pages per cpu */
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#define TOTAL_SWITCHER_PAGES (SHARED_SWITCHER_PAGES + 2 * nr_cpu_ids)
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/* We map at -4M for ease of mapping into the guest (one PTE page). */
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/* We map at -4M (-2M when PAE is activated) for ease of mapping
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* into the guest (one PTE page). */
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#ifdef CONFIG_X86_PAE
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#define SWITCHER_ADDR 0xFFE00000
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#else
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#define SWITCHER_ADDR 0xFFC00000
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#endif
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/* Found in switcher.S */
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extern unsigned long default_idt_entries[];
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@ -12,6 +12,7 @@
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#define LHCALL_TS 8
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#define LHCALL_SET_CLOCKEVENT 9
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#define LHCALL_HALT 10
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#define LHCALL_SET_PMD 13
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#define LHCALL_SET_PTE 14
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#define LHCALL_SET_PGD 15
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#define LHCALL_LOAD_TLS 16
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@ -33,7 +34,7 @@
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* operations? There are two ways: the direct way is to make a "hypercall",
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* to make requests of the Host Itself.
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*
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* We use the KVM hypercall mechanism. Eighteen hypercalls are
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* We use the KVM hypercall mechanism. Seventeen hypercalls are
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* available: the hypercall number is put in the %eax register, and the
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* arguments (when required) are placed in %ebx, %ecx, %edx and %esi.
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* If a return value makes sense, it's returned in %eax.
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@ -2,7 +2,6 @@ config LGUEST_GUEST
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bool "Lguest guest support"
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select PARAVIRT
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depends on X86_32
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depends on !X86_PAE
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select VIRTIO
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select VIRTIO_RING
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select VIRTIO_CONSOLE
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@ -167,6 +167,7 @@ static void lazy_hcall3(unsigned long call,
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async_hcall(call, arg1, arg2, arg3, 0);
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}
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#ifdef CONFIG_X86_PAE
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static void lazy_hcall4(unsigned long call,
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unsigned long arg1,
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unsigned long arg2,
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@ -178,6 +179,7 @@ static void lazy_hcall4(unsigned long call,
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else
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async_hcall(call, arg1, arg2, arg3, arg4);
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}
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#endif
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/* When lazy mode is turned off reset the per-cpu lazy mode variable and then
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* issue the do-nothing hypercall to flush any stored calls. */
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@ -380,8 +382,8 @@ static void lguest_cpuid(unsigned int *ax, unsigned int *bx,
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case 1: /* Basic feature request. */
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/* We only allow kernel to see SSE3, CMPXCHG16B and SSSE3 */
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*cx &= 0x00002201;
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/* SSE, SSE2, FXSR, MMX, CMOV, CMPXCHG8B, TSC, FPU. */
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*dx &= 0x07808111;
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/* SSE, SSE2, FXSR, MMX, CMOV, CMPXCHG8B, TSC, FPU, PAE. */
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*dx &= 0x07808151;
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/* The Host can do a nice optimization if it knows that the
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* kernel mappings (addresses above 0xC0000000 or whatever
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* PAGE_OFFSET is set to) haven't changed. But Linux calls
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@ -400,6 +402,11 @@ static void lguest_cpuid(unsigned int *ax, unsigned int *bx,
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if (*ax > 0x80000008)
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*ax = 0x80000008;
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break;
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case 0x80000001:
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/* Here we should fix nx cap depending on host. */
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/* For this version of PAE, we just clear NX bit. */
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*dx &= ~(1 << 20);
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break;
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}
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}
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@ -533,7 +540,12 @@ static void lguest_write_cr4(unsigned long val)
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static void lguest_pte_update(struct mm_struct *mm, unsigned long addr,
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pte_t *ptep)
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{
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#ifdef CONFIG_X86_PAE
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lazy_hcall4(LHCALL_SET_PTE, __pa(mm->pgd), addr,
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ptep->pte_low, ptep->pte_high);
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#else
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lazy_hcall3(LHCALL_SET_PTE, __pa(mm->pgd), addr, ptep->pte_low);
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#endif
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}
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static void lguest_set_pte_at(struct mm_struct *mm, unsigned long addr,
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@ -543,15 +555,37 @@ static void lguest_set_pte_at(struct mm_struct *mm, unsigned long addr,
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lguest_pte_update(mm, addr, ptep);
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}
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/* The Guest calls this to set a top-level entry. Again, we set the entry then
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* tell the Host which top-level page we changed, and the index of the entry we
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* changed. */
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/* The Guest calls lguest_set_pud to set a top-level entry and lguest_set_pmd
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* to set a middle-level entry when PAE is activated.
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* Again, we set the entry then tell the Host which page we changed,
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* and the index of the entry we changed. */
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#ifdef CONFIG_X86_PAE
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static void lguest_set_pud(pud_t *pudp, pud_t pudval)
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{
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native_set_pud(pudp, pudval);
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/* 32 bytes aligned pdpt address and the index. */
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lazy_hcall2(LHCALL_SET_PGD, __pa(pudp) & 0xFFFFFFE0,
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(__pa(pudp) & 0x1F) / sizeof(pud_t));
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}
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static void lguest_set_pmd(pmd_t *pmdp, pmd_t pmdval)
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{
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native_set_pmd(pmdp, pmdval);
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lazy_hcall2(LHCALL_SET_PMD, __pa(pmdp) & PAGE_MASK,
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(__pa(pmdp) & (PAGE_SIZE - 1)) / sizeof(pmd_t));
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}
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#else
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/* The Guest calls lguest_set_pmd to set a top-level entry when PAE is not
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* activated. */
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static void lguest_set_pmd(pmd_t *pmdp, pmd_t pmdval)
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{
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native_set_pmd(pmdp, pmdval);
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lazy_hcall2(LHCALL_SET_PGD, __pa(pmdp) & PAGE_MASK,
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(__pa(pmdp) & (PAGE_SIZE - 1)) / sizeof(pmd_t));
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}
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#endif
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/* There are a couple of legacy places where the kernel sets a PTE, but we
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* don't know the top level any more. This is useless for us, since we don't
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@ -569,6 +603,26 @@ static void lguest_set_pte(pte_t *ptep, pte_t pteval)
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lazy_hcall1(LHCALL_FLUSH_TLB, 1);
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}
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#ifdef CONFIG_X86_PAE
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static void lguest_set_pte_atomic(pte_t *ptep, pte_t pte)
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{
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native_set_pte_atomic(ptep, pte);
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if (cr3_changed)
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lazy_hcall1(LHCALL_FLUSH_TLB, 1);
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}
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void lguest_pte_clear(struct mm_struct *mm, unsigned long addr, pte_t *ptep)
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{
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native_pte_clear(mm, addr, ptep);
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lguest_pte_update(mm, addr, ptep);
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}
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void lguest_pmd_clear(pmd_t *pmdp)
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{
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lguest_set_pmd(pmdp, __pmd(0));
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}
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#endif
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/* Unfortunately for Lguest, the pv_mmu_ops for page tables were based on
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* native page table operations. On native hardware you can set a new page
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* table entry whenever you want, but if you want to remove one you have to do
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@ -1035,6 +1089,7 @@ __init void lguest_init(void)
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pv_info.name = "lguest";
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pv_info.paravirt_enabled = 1;
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pv_info.kernel_rpl = 1;
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pv_info.shared_kernel_pmd = 1;
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/* We set up all the lguest overrides for sensitive operations. These
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* are detailed with the operations themselves. */
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@ -1080,6 +1135,12 @@ __init void lguest_init(void)
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pv_mmu_ops.set_pte = lguest_set_pte;
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pv_mmu_ops.set_pte_at = lguest_set_pte_at;
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pv_mmu_ops.set_pmd = lguest_set_pmd;
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#ifdef CONFIG_X86_PAE
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pv_mmu_ops.set_pte_atomic = lguest_set_pte_atomic;
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pv_mmu_ops.pte_clear = lguest_pte_clear;
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pv_mmu_ops.pmd_clear = lguest_pmd_clear;
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pv_mmu_ops.set_pud = lguest_set_pud;
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#endif
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pv_mmu_ops.read_cr2 = lguest_read_cr2;
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pv_mmu_ops.read_cr3 = lguest_read_cr3;
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pv_mmu_ops.lazy_mode.enter = paravirt_enter_lazy_mmu;
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@ -1,6 +1,6 @@
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config LGUEST
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tristate "Linux hypervisor example code"
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depends on X86_32 && EXPERIMENTAL && !X86_PAE && FUTEX
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depends on X86_32 && EXPERIMENTAL && FUTEX
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select HVC_DRIVER
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---help---
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This is a very simple module which allows you to run
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@ -77,11 +77,21 @@ static void do_hcall(struct lg_cpu *cpu, struct hcall_args *args)
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guest_set_stack(cpu, args->arg1, args->arg2, args->arg3);
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break;
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case LHCALL_SET_PTE:
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#ifdef CONFIG_X86_PAE
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guest_set_pte(cpu, args->arg1, args->arg2,
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__pte(args->arg3 | (u64)args->arg4 << 32));
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#else
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guest_set_pte(cpu, args->arg1, args->arg2, __pte(args->arg3));
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#endif
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break;
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case LHCALL_SET_PGD:
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guest_set_pgd(cpu->lg, args->arg1, args->arg2);
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break;
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#ifdef CONFIG_X86_PAE
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case LHCALL_SET_PMD:
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guest_set_pmd(cpu->lg, args->arg1, args->arg2);
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break;
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#endif
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case LHCALL_SET_CLOCKEVENT:
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guest_set_clockevent(cpu, args->arg1);
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break;
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@ -137,6 +137,8 @@ int run_guest(struct lg_cpu *cpu, unsigned long __user *user);
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* in the kernel. */
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#define pgd_flags(x) (pgd_val(x) & ~PAGE_MASK)
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#define pgd_pfn(x) (pgd_val(x) >> PAGE_SHIFT)
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#define pmd_flags(x) (pmd_val(x) & ~PAGE_MASK)
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#define pmd_pfn(x) (pmd_val(x) >> PAGE_SHIFT)
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/* interrupts_and_traps.c: */
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unsigned int interrupt_pending(struct lg_cpu *cpu, bool *more);
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@ -170,6 +172,9 @@ int init_guest_pagetable(struct lguest *lg);
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void free_guest_pagetable(struct lguest *lg);
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void guest_new_pagetable(struct lg_cpu *cpu, unsigned long pgtable);
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void guest_set_pgd(struct lguest *lg, unsigned long gpgdir, u32 i);
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#ifdef CONFIG_X86_PAE
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void guest_set_pmd(struct lguest *lg, unsigned long gpgdir, u32 i);
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#endif
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void guest_pagetable_clear_all(struct lg_cpu *cpu);
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void guest_pagetable_flush_user(struct lg_cpu *cpu);
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void guest_set_pte(struct lg_cpu *cpu, unsigned long gpgdir,
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@ -53,6 +53,17 @@
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* page. */
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#define SWITCHER_PGD_INDEX (PTRS_PER_PGD - 1)
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/* For PAE we need the PMD index as well. We use the last 2MB, so we
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* will need the last pmd entry of the last pmd page. */
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#ifdef CONFIG_X86_PAE
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#define SWITCHER_PMD_INDEX (PTRS_PER_PMD - 1)
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#define RESERVE_MEM 2U
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#define CHECK_GPGD_MASK _PAGE_PRESENT
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#else
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#define RESERVE_MEM 4U
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#define CHECK_GPGD_MASK _PAGE_TABLE
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#endif
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/* We actually need a separate PTE page for each CPU. Remember that after the
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* Switcher code itself comes two pages for each CPU, and we don't want this
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* CPU's guest to see the pages of any other CPU. */
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@ -73,23 +84,58 @@ static pgd_t *spgd_addr(struct lg_cpu *cpu, u32 i, unsigned long vaddr)
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{
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unsigned int index = pgd_index(vaddr);
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#ifndef CONFIG_X86_PAE
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/* We kill any Guest trying to touch the Switcher addresses. */
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if (index >= SWITCHER_PGD_INDEX) {
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kill_guest(cpu, "attempt to access switcher pages");
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index = 0;
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}
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#endif
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/* Return a pointer index'th pgd entry for the i'th page table. */
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return &cpu->lg->pgdirs[i].pgdir[index];
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}
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#ifdef CONFIG_X86_PAE
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/* This routine then takes the PGD entry given above, which contains the
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* address of the PMD page. It then returns a pointer to the PMD entry for the
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* given address. */
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static pmd_t *spmd_addr(struct lg_cpu *cpu, pgd_t spgd, unsigned long vaddr)
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{
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unsigned int index = pmd_index(vaddr);
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pmd_t *page;
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/* We kill any Guest trying to touch the Switcher addresses. */
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if (pgd_index(vaddr) == SWITCHER_PGD_INDEX &&
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index >= SWITCHER_PMD_INDEX) {
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kill_guest(cpu, "attempt to access switcher pages");
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index = 0;
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}
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/* You should never call this if the PGD entry wasn't valid */
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BUG_ON(!(pgd_flags(spgd) & _PAGE_PRESENT));
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page = __va(pgd_pfn(spgd) << PAGE_SHIFT);
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return &page[index];
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}
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#endif
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/* This routine then takes the page directory entry returned above, which
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* contains the address of the page table entry (PTE) page. It then returns a
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* pointer to the PTE entry for the given address. */
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static pte_t *spte_addr(pgd_t spgd, unsigned long vaddr)
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static pte_t *spte_addr(struct lg_cpu *cpu, pgd_t spgd, unsigned long vaddr)
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{
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#ifdef CONFIG_X86_PAE
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pmd_t *pmd = spmd_addr(cpu, spgd, vaddr);
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pte_t *page = __va(pmd_pfn(*pmd) << PAGE_SHIFT);
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/* You should never call this if the PMD entry wasn't valid */
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BUG_ON(!(pmd_flags(*pmd) & _PAGE_PRESENT));
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#else
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pte_t *page = __va(pgd_pfn(spgd) << PAGE_SHIFT);
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/* You should never call this if the PGD entry wasn't valid */
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BUG_ON(!(pgd_flags(spgd) & _PAGE_PRESENT));
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#endif
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return &page[pte_index(vaddr)];
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}
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@ -101,10 +147,31 @@ static unsigned long gpgd_addr(struct lg_cpu *cpu, unsigned long vaddr)
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return cpu->lg->pgdirs[cpu->cpu_pgd].gpgdir + index * sizeof(pgd_t);
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}
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static unsigned long gpte_addr(pgd_t gpgd, unsigned long vaddr)
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#ifdef CONFIG_X86_PAE
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static unsigned long gpmd_addr(pgd_t gpgd, unsigned long vaddr)
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{
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unsigned long gpage = pgd_pfn(gpgd) << PAGE_SHIFT;
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BUG_ON(!(pgd_flags(gpgd) & _PAGE_PRESENT));
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return gpage + pmd_index(vaddr) * sizeof(pmd_t);
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}
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#endif
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static unsigned long gpte_addr(struct lg_cpu *cpu,
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pgd_t gpgd, unsigned long vaddr)
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{
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#ifdef CONFIG_X86_PAE
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pmd_t gpmd;
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#endif
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unsigned long gpage;
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BUG_ON(!(pgd_flags(gpgd) & _PAGE_PRESENT));
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#ifdef CONFIG_X86_PAE
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gpmd = lgread(cpu, gpmd_addr(gpgd, vaddr), pmd_t);
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gpage = pmd_pfn(gpmd) << PAGE_SHIFT;
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BUG_ON(!(pmd_flags(gpmd) & _PAGE_PRESENT));
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#else
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gpage = pgd_pfn(gpgd) << PAGE_SHIFT;
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#endif
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return gpage + pte_index(vaddr) * sizeof(pte_t);
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}
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/*:*/
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@ -184,11 +251,20 @@ static void check_gpte(struct lg_cpu *cpu, pte_t gpte)
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static void check_gpgd(struct lg_cpu *cpu, pgd_t gpgd)
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{
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if ((pgd_flags(gpgd) & ~_PAGE_TABLE) ||
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if ((pgd_flags(gpgd) & ~CHECK_GPGD_MASK) ||
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(pgd_pfn(gpgd) >= cpu->lg->pfn_limit))
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kill_guest(cpu, "bad page directory entry");
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}
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#ifdef CONFIG_X86_PAE
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static void check_gpmd(struct lg_cpu *cpu, pmd_t gpmd)
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{
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if ((pmd_flags(gpmd) & ~_PAGE_TABLE) ||
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(pmd_pfn(gpmd) >= cpu->lg->pfn_limit))
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kill_guest(cpu, "bad page middle directory entry");
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}
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#endif
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/*H:330
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* (i) Looking up a page table entry when the Guest faults.
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*
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@ -207,6 +283,11 @@ bool demand_page(struct lg_cpu *cpu, unsigned long vaddr, int errcode)
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pte_t gpte;
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pte_t *spte;
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#ifdef CONFIG_X86_PAE
|
||||
pmd_t *spmd;
|
||||
pmd_t gpmd;
|
||||
#endif
|
||||
|
||||
/* First step: get the top-level Guest page table entry. */
|
||||
gpgd = lgread(cpu, gpgd_addr(cpu, vaddr), pgd_t);
|
||||
/* Toplevel not present? We can't map it in. */
|
||||
|
|
@ -228,12 +309,40 @@ bool demand_page(struct lg_cpu *cpu, unsigned long vaddr, int errcode)
|
|||
check_gpgd(cpu, gpgd);
|
||||
/* And we copy the flags to the shadow PGD entry. The page
|
||||
* number in the shadow PGD is the page we just allocated. */
|
||||
*spgd = __pgd(__pa(ptepage) | pgd_flags(gpgd));
|
||||
set_pgd(spgd, __pgd(__pa(ptepage) | pgd_flags(gpgd)));
|
||||
}
|
||||
|
||||
#ifdef CONFIG_X86_PAE
|
||||
gpmd = lgread(cpu, gpmd_addr(gpgd, vaddr), pmd_t);
|
||||
/* middle level not present? We can't map it in. */
|
||||
if (!(pmd_flags(gpmd) & _PAGE_PRESENT))
|
||||
return false;
|
||||
|
||||
/* Now look at the matching shadow entry. */
|
||||
spmd = spmd_addr(cpu, *spgd, vaddr);
|
||||
|
||||
if (!(pmd_flags(*spmd) & _PAGE_PRESENT)) {
|
||||
/* No shadow entry: allocate a new shadow PTE page. */
|
||||
unsigned long ptepage = get_zeroed_page(GFP_KERNEL);
|
||||
|
||||
/* This is not really the Guest's fault, but killing it is
|
||||
* simple for this corner case. */
|
||||
if (!ptepage) {
|
||||
kill_guest(cpu, "out of memory allocating pte page");
|
||||
return false;
|
||||
}
|
||||
|
||||
/* We check that the Guest pmd is OK. */
|
||||
check_gpmd(cpu, gpmd);
|
||||
|
||||
/* And we copy the flags to the shadow PMD entry. The page
|
||||
* number in the shadow PMD is the page we just allocated. */
|
||||
native_set_pmd(spmd, __pmd(__pa(ptepage) | pmd_flags(gpmd)));
|
||||
}
|
||||
#endif
|
||||
/* OK, now we look at the lower level in the Guest page table: keep its
|
||||
* address, because we might update it later. */
|
||||
gpte_ptr = gpte_addr(gpgd, vaddr);
|
||||
gpte_ptr = gpte_addr(cpu, gpgd, vaddr);
|
||||
gpte = lgread(cpu, gpte_ptr, pte_t);
|
||||
|
||||
/* If this page isn't in the Guest page tables, we can't page it in. */
|
||||
|
|
@ -259,7 +368,7 @@ bool demand_page(struct lg_cpu *cpu, unsigned long vaddr, int errcode)
|
|||
gpte = pte_mkdirty(gpte);
|
||||
|
||||
/* Get the pointer to the shadow PTE entry we're going to set. */
|
||||
spte = spte_addr(*spgd, vaddr);
|
||||
spte = spte_addr(cpu, *spgd, vaddr);
|
||||
/* If there was a valid shadow PTE entry here before, we release it.
|
||||
* This can happen with a write to a previously read-only entry. */
|
||||
release_pte(*spte);
|
||||
|
|
@ -301,14 +410,23 @@ static bool page_writable(struct lg_cpu *cpu, unsigned long vaddr)
|
|||
pgd_t *spgd;
|
||||
unsigned long flags;
|
||||
|
||||
#ifdef CONFIG_X86_PAE
|
||||
pmd_t *spmd;
|
||||
#endif
|
||||
/* Look at the current top level entry: is it present? */
|
||||
spgd = spgd_addr(cpu, cpu->cpu_pgd, vaddr);
|
||||
if (!(pgd_flags(*spgd) & _PAGE_PRESENT))
|
||||
return false;
|
||||
|
||||
#ifdef CONFIG_X86_PAE
|
||||
spmd = spmd_addr(cpu, *spgd, vaddr);
|
||||
if (!(pmd_flags(*spmd) & _PAGE_PRESENT))
|
||||
return false;
|
||||
#endif
|
||||
|
||||
/* Check the flags on the pte entry itself: it must be present and
|
||||
* writable. */
|
||||
flags = pte_flags(*(spte_addr(*spgd, vaddr)));
|
||||
flags = pte_flags(*(spte_addr(cpu, *spgd, vaddr)));
|
||||
|
||||
return (flags & (_PAGE_PRESENT|_PAGE_RW)) == (_PAGE_PRESENT|_PAGE_RW);
|
||||
}
|
||||
|
|
@ -322,6 +440,41 @@ void pin_page(struct lg_cpu *cpu, unsigned long vaddr)
|
|||
kill_guest(cpu, "bad stack page %#lx", vaddr);
|
||||
}
|
||||
|
||||
#ifdef CONFIG_X86_PAE
|
||||
static void release_pmd(pmd_t *spmd)
|
||||
{
|
||||
/* If the entry's not present, there's nothing to release. */
|
||||
if (pmd_flags(*spmd) & _PAGE_PRESENT) {
|
||||
unsigned int i;
|
||||
pte_t *ptepage = __va(pmd_pfn(*spmd) << PAGE_SHIFT);
|
||||
/* For each entry in the page, we might need to release it. */
|
||||
for (i = 0; i < PTRS_PER_PTE; i++)
|
||||
release_pte(ptepage[i]);
|
||||
/* Now we can free the page of PTEs */
|
||||
free_page((long)ptepage);
|
||||
/* And zero out the PMD entry so we never release it twice. */
|
||||
native_set_pmd(spmd, __pmd(0));
|
||||
}
|
||||
}
|
||||
|
||||
static void release_pgd(pgd_t *spgd)
|
||||
{
|
||||
/* If the entry's not present, there's nothing to release. */
|
||||
if (pgd_flags(*spgd) & _PAGE_PRESENT) {
|
||||
unsigned int i;
|
||||
pmd_t *pmdpage = __va(pgd_pfn(*spgd) << PAGE_SHIFT);
|
||||
|
||||
for (i = 0; i < PTRS_PER_PMD; i++)
|
||||
release_pmd(&pmdpage[i]);
|
||||
|
||||
/* Now we can free the page of PMDs */
|
||||
free_page((long)pmdpage);
|
||||
/* And zero out the PGD entry so we never release it twice. */
|
||||
set_pgd(spgd, __pgd(0));
|
||||
}
|
||||
}
|
||||
|
||||
#else /* !CONFIG_X86_PAE */
|
||||
/*H:450 If we chase down the release_pgd() code, it looks like this: */
|
||||
static void release_pgd(pgd_t *spgd)
|
||||
{
|
||||
|
|
@ -341,7 +494,7 @@ static void release_pgd(pgd_t *spgd)
|
|||
*spgd = __pgd(0);
|
||||
}
|
||||
}
|
||||
|
||||
#endif
|
||||
/*H:445 We saw flush_user_mappings() twice: once from the flush_user_mappings()
|
||||
* hypercall and once in new_pgdir() when we re-used a top-level pgdir page.
|
||||
* It simply releases every PTE page from 0 up to the Guest's kernel address. */
|
||||
|
|
@ -370,6 +523,9 @@ unsigned long guest_pa(struct lg_cpu *cpu, unsigned long vaddr)
|
|||
pgd_t gpgd;
|
||||
pte_t gpte;
|
||||
|
||||
#ifdef CONFIG_X86_PAE
|
||||
pmd_t gpmd;
|
||||
#endif
|
||||
/* First step: get the top-level Guest page table entry. */
|
||||
gpgd = lgread(cpu, gpgd_addr(cpu, vaddr), pgd_t);
|
||||
/* Toplevel not present? We can't map it in. */
|
||||
|
|
@ -378,7 +534,13 @@ unsigned long guest_pa(struct lg_cpu *cpu, unsigned long vaddr)
|
|||
return -1UL;
|
||||
}
|
||||
|
||||
gpte = lgread(cpu, gpte_addr(gpgd, vaddr), pte_t);
|
||||
gpte = lgread(cpu, gpte_addr(cpu, gpgd, vaddr), pte_t);
|
||||
#ifdef CONFIG_X86_PAE
|
||||
gpmd = lgread(cpu, gpmd_addr(gpgd, vaddr), pmd_t);
|
||||
if (!(pmd_flags(gpmd) & _PAGE_PRESENT))
|
||||
kill_guest(cpu, "Bad address %#lx", vaddr);
|
||||
#endif
|
||||
gpte = lgread(cpu, gpte_addr(cpu, gpgd, vaddr), pte_t);
|
||||
if (!(pte_flags(gpte) & _PAGE_PRESENT))
|
||||
kill_guest(cpu, "Bad address %#lx", vaddr);
|
||||
|
||||
|
|
@ -405,6 +567,9 @@ static unsigned int new_pgdir(struct lg_cpu *cpu,
|
|||
int *blank_pgdir)
|
||||
{
|
||||
unsigned int next;
|
||||
#ifdef CONFIG_X86_PAE
|
||||
pmd_t *pmd_table;
|
||||
#endif
|
||||
|
||||
/* We pick one entry at random to throw out. Choosing the Least
|
||||
* Recently Used might be better, but this is easy. */
|
||||
|
|
@ -416,10 +581,27 @@ static unsigned int new_pgdir(struct lg_cpu *cpu,
|
|||
/* If the allocation fails, just keep using the one we have */
|
||||
if (!cpu->lg->pgdirs[next].pgdir)
|
||||
next = cpu->cpu_pgd;
|
||||
else
|
||||
/* This is a blank page, so there are no kernel
|
||||
* mappings: caller must map the stack! */
|
||||
else {
|
||||
#ifdef CONFIG_X86_PAE
|
||||
/* In PAE mode, allocate a pmd page and populate the
|
||||
* last pgd entry. */
|
||||
pmd_table = (pmd_t *)get_zeroed_page(GFP_KERNEL);
|
||||
if (!pmd_table) {
|
||||
free_page((long)cpu->lg->pgdirs[next].pgdir);
|
||||
set_pgd(cpu->lg->pgdirs[next].pgdir, __pgd(0));
|
||||
next = cpu->cpu_pgd;
|
||||
} else {
|
||||
set_pgd(cpu->lg->pgdirs[next].pgdir +
|
||||
SWITCHER_PGD_INDEX,
|
||||
__pgd(__pa(pmd_table) | _PAGE_PRESENT));
|
||||
/* This is a blank page, so there are no kernel
|
||||
* mappings: caller must map the stack! */
|
||||
*blank_pgdir = 1;
|
||||
}
|
||||
#else
|
||||
*blank_pgdir = 1;
|
||||
#endif
|
||||
}
|
||||
}
|
||||
/* Record which Guest toplevel this shadows. */
|
||||
cpu->lg->pgdirs[next].gpgdir = gpgdir;
|
||||
|
|
@ -460,10 +642,25 @@ static void release_all_pagetables(struct lguest *lg)
|
|||
|
||||
/* Every shadow pagetable this Guest has */
|
||||
for (i = 0; i < ARRAY_SIZE(lg->pgdirs); i++)
|
||||
if (lg->pgdirs[i].pgdir)
|
||||
if (lg->pgdirs[i].pgdir) {
|
||||
#ifdef CONFIG_X86_PAE
|
||||
pgd_t *spgd;
|
||||
pmd_t *pmdpage;
|
||||
unsigned int k;
|
||||
|
||||
/* Get the last pmd page. */
|
||||
spgd = lg->pgdirs[i].pgdir + SWITCHER_PGD_INDEX;
|
||||
pmdpage = __va(pgd_pfn(*spgd) << PAGE_SHIFT);
|
||||
|
||||
/* And release the pmd entries of that pmd page,
|
||||
* except for the switcher pmd. */
|
||||
for (k = 0; k < SWITCHER_PMD_INDEX; k++)
|
||||
release_pmd(&pmdpage[k]);
|
||||
#endif
|
||||
/* Every PGD entry except the Switcher at the top */
|
||||
for (j = 0; j < SWITCHER_PGD_INDEX; j++)
|
||||
release_pgd(lg->pgdirs[i].pgdir + j);
|
||||
}
|
||||
}
|
||||
|
||||
/* We also throw away everything when a Guest tells us it's changed a kernel
|
||||
|
|
@ -504,24 +701,37 @@ static void do_set_pte(struct lg_cpu *cpu, int idx,
|
|||
{
|
||||
/* Look up the matching shadow page directory entry. */
|
||||
pgd_t *spgd = spgd_addr(cpu, idx, vaddr);
|
||||
#ifdef CONFIG_X86_PAE
|
||||
pmd_t *spmd;
|
||||
#endif
|
||||
|
||||
/* If the top level isn't present, there's no entry to update. */
|
||||
if (pgd_flags(*spgd) & _PAGE_PRESENT) {
|
||||
/* Otherwise, we start by releasing the existing entry. */
|
||||
pte_t *spte = spte_addr(*spgd, vaddr);
|
||||
release_pte(*spte);
|
||||
#ifdef CONFIG_X86_PAE
|
||||
spmd = spmd_addr(cpu, *spgd, vaddr);
|
||||
if (pmd_flags(*spmd) & _PAGE_PRESENT) {
|
||||
#endif
|
||||
/* Otherwise, we start by releasing
|
||||
* the existing entry. */
|
||||
pte_t *spte = spte_addr(cpu, *spgd, vaddr);
|
||||
release_pte(*spte);
|
||||
|
||||
/* If they're setting this entry as dirty or accessed, we might
|
||||
* as well put that entry they've given us in now. This shaves
|
||||
* 10% off a copy-on-write micro-benchmark. */
|
||||
if (pte_flags(gpte) & (_PAGE_DIRTY | _PAGE_ACCESSED)) {
|
||||
check_gpte(cpu, gpte);
|
||||
*spte = gpte_to_spte(cpu, gpte,
|
||||
pte_flags(gpte) & _PAGE_DIRTY);
|
||||
} else
|
||||
/* Otherwise kill it and we can demand_page() it in
|
||||
* later. */
|
||||
*spte = __pte(0);
|
||||
/* If they're setting this entry as dirty or accessed,
|
||||
* we might as well put that entry they've given us
|
||||
* in now. This shaves 10% off a
|
||||
* copy-on-write micro-benchmark. */
|
||||
if (pte_flags(gpte) & (_PAGE_DIRTY | _PAGE_ACCESSED)) {
|
||||
check_gpte(cpu, gpte);
|
||||
native_set_pte(spte,
|
||||
gpte_to_spte(cpu, gpte,
|
||||
pte_flags(gpte) & _PAGE_DIRTY));
|
||||
} else
|
||||
/* Otherwise kill it and we can demand_page()
|
||||
* it in later. */
|
||||
native_set_pte(spte, __pte(0));
|
||||
#ifdef CONFIG_X86_PAE
|
||||
}
|
||||
#endif
|
||||
}
|
||||
}
|
||||
|
||||
|
|
@ -572,8 +782,6 @@ void guest_set_pgd(struct lguest *lg, unsigned long gpgdir, u32 idx)
|
|||
{
|
||||
int pgdir;
|
||||
|
||||
/* The kernel seems to try to initialize this early on: we ignore its
|
||||
* attempts to map over the Switcher. */
|
||||
if (idx >= SWITCHER_PGD_INDEX)
|
||||
return;
|
||||
|
||||
|
|
@ -583,6 +791,12 @@ void guest_set_pgd(struct lguest *lg, unsigned long gpgdir, u32 idx)
|
|||
/* ... throw it away. */
|
||||
release_pgd(lg->pgdirs[pgdir].pgdir + idx);
|
||||
}
|
||||
#ifdef CONFIG_X86_PAE
|
||||
void guest_set_pmd(struct lguest *lg, unsigned long pmdp, u32 idx)
|
||||
{
|
||||
guest_pagetable_clear_all(&lg->cpus[0]);
|
||||
}
|
||||
#endif
|
||||
|
||||
/* Once we know how much memory we have we can construct simple identity
|
||||
* (which set virtual == physical) and linear mappings
|
||||
|
|
@ -596,8 +810,16 @@ static unsigned long setup_pagetables(struct lguest *lg,
|
|||
{
|
||||
pgd_t __user *pgdir;
|
||||
pte_t __user *linear;
|
||||
unsigned int mapped_pages, i, linear_pages, phys_linear;
|
||||
unsigned long mem_base = (unsigned long)lg->mem_base;
|
||||
unsigned int mapped_pages, i, linear_pages;
|
||||
#ifdef CONFIG_X86_PAE
|
||||
pmd_t __user *pmds;
|
||||
unsigned int j;
|
||||
pgd_t pgd;
|
||||
pmd_t pmd;
|
||||
#else
|
||||
unsigned int phys_linear;
|
||||
#endif
|
||||
|
||||
/* We have mapped_pages frames to map, so we need
|
||||
* linear_pages page tables to map them. */
|
||||
|
|
@ -610,6 +832,9 @@ static unsigned long setup_pagetables(struct lguest *lg,
|
|||
/* Now we use the next linear_pages pages as pte pages */
|
||||
linear = (void *)pgdir - linear_pages * PAGE_SIZE;
|
||||
|
||||
#ifdef CONFIG_X86_PAE
|
||||
pmds = (void *)linear - PAGE_SIZE;
|
||||
#endif
|
||||
/* Linear mapping is easy: put every page's address into the
|
||||
* mapping in order. */
|
||||
for (i = 0; i < mapped_pages; i++) {
|
||||
|
|
@ -621,6 +846,22 @@ static unsigned long setup_pagetables(struct lguest *lg,
|
|||
|
||||
/* The top level points to the linear page table pages above.
|
||||
* We setup the identity and linear mappings here. */
|
||||
#ifdef CONFIG_X86_PAE
|
||||
for (i = 0, j; i < mapped_pages && j < PTRS_PER_PMD;
|
||||
i += PTRS_PER_PTE, j++) {
|
||||
native_set_pmd(&pmd, __pmd(((unsigned long)(linear + i)
|
||||
- mem_base) | _PAGE_PRESENT | _PAGE_RW | _PAGE_USER));
|
||||
|
||||
if (copy_to_user(&pmds[j], &pmd, sizeof(pmd)) != 0)
|
||||
return -EFAULT;
|
||||
}
|
||||
|
||||
set_pgd(&pgd, __pgd(((u32)pmds - mem_base) | _PAGE_PRESENT));
|
||||
if (copy_to_user(&pgdir[0], &pgd, sizeof(pgd)) != 0)
|
||||
return -EFAULT;
|
||||
if (copy_to_user(&pgdir[3], &pgd, sizeof(pgd)) != 0)
|
||||
return -EFAULT;
|
||||
#else
|
||||
phys_linear = (unsigned long)linear - mem_base;
|
||||
for (i = 0; i < mapped_pages; i += PTRS_PER_PTE) {
|
||||
pgd_t pgd;
|
||||
|
|
@ -633,6 +874,7 @@ static unsigned long setup_pagetables(struct lguest *lg,
|
|||
&pgd, sizeof(pgd)))
|
||||
return -EFAULT;
|
||||
}
|
||||
#endif
|
||||
|
||||
/* We return the top level (guest-physical) address: remember where
|
||||
* this is. */
|
||||
|
|
@ -648,7 +890,10 @@ int init_guest_pagetable(struct lguest *lg)
|
|||
u64 mem;
|
||||
u32 initrd_size;
|
||||
struct boot_params __user *boot = (struct boot_params *)lg->mem_base;
|
||||
|
||||
#ifdef CONFIG_X86_PAE
|
||||
pgd_t *pgd;
|
||||
pmd_t *pmd_table;
|
||||
#endif
|
||||
/* Get the Guest memory size and the ramdisk size from the boot header
|
||||
* located at lg->mem_base (Guest address 0). */
|
||||
if (copy_from_user(&mem, &boot->e820_map[0].size, sizeof(mem))
|
||||
|
|
@ -663,6 +908,15 @@ int init_guest_pagetable(struct lguest *lg)
|
|||
lg->pgdirs[0].pgdir = (pgd_t *)get_zeroed_page(GFP_KERNEL);
|
||||
if (!lg->pgdirs[0].pgdir)
|
||||
return -ENOMEM;
|
||||
#ifdef CONFIG_X86_PAE
|
||||
pgd = lg->pgdirs[0].pgdir;
|
||||
pmd_table = (pmd_t *) get_zeroed_page(GFP_KERNEL);
|
||||
if (!pmd_table)
|
||||
return -ENOMEM;
|
||||
|
||||
set_pgd(pgd + SWITCHER_PGD_INDEX,
|
||||
__pgd(__pa(pmd_table) | _PAGE_PRESENT));
|
||||
#endif
|
||||
lg->cpus[0].cpu_pgd = 0;
|
||||
return 0;
|
||||
}
|
||||
|
|
@ -672,17 +926,24 @@ void page_table_guest_data_init(struct lg_cpu *cpu)
|
|||
{
|
||||
/* We get the kernel address: above this is all kernel memory. */
|
||||
if (get_user(cpu->lg->kernel_address,
|
||||
&cpu->lg->lguest_data->kernel_address)
|
||||
/* We tell the Guest that it can't use the top 4MB of virtual
|
||||
* addresses used by the Switcher. */
|
||||
|| put_user(4U*1024*1024, &cpu->lg->lguest_data->reserve_mem)
|
||||
|| put_user(cpu->lg->pgdirs[0].gpgdir, &cpu->lg->lguest_data->pgdir))
|
||||
&cpu->lg->lguest_data->kernel_address)
|
||||
/* We tell the Guest that it can't use the top 2 or 4 MB
|
||||
* of virtual addresses used by the Switcher. */
|
||||
|| put_user(RESERVE_MEM * 1024 * 1024,
|
||||
&cpu->lg->lguest_data->reserve_mem)
|
||||
|| put_user(cpu->lg->pgdirs[0].gpgdir,
|
||||
&cpu->lg->lguest_data->pgdir))
|
||||
kill_guest(cpu, "bad guest page %p", cpu->lg->lguest_data);
|
||||
|
||||
/* In flush_user_mappings() we loop from 0 to
|
||||
* "pgd_index(lg->kernel_address)". This assumes it won't hit the
|
||||
* Switcher mappings, so check that now. */
|
||||
#ifdef CONFIG_X86_PAE
|
||||
if (pgd_index(cpu->lg->kernel_address) == SWITCHER_PGD_INDEX &&
|
||||
pmd_index(cpu->lg->kernel_address) == SWITCHER_PMD_INDEX)
|
||||
#else
|
||||
if (pgd_index(cpu->lg->kernel_address) >= SWITCHER_PGD_INDEX)
|
||||
#endif
|
||||
kill_guest(cpu, "bad kernel address %#lx",
|
||||
cpu->lg->kernel_address);
|
||||
}
|
||||
|
|
@ -708,16 +969,30 @@ void free_guest_pagetable(struct lguest *lg)
|
|||
void map_switcher_in_guest(struct lg_cpu *cpu, struct lguest_pages *pages)
|
||||
{
|
||||
pte_t *switcher_pte_page = __get_cpu_var(switcher_pte_pages);
|
||||
pgd_t switcher_pgd;
|
||||
pte_t regs_pte;
|
||||
unsigned long pfn;
|
||||
|
||||
#ifdef CONFIG_X86_PAE
|
||||
pmd_t switcher_pmd;
|
||||
pmd_t *pmd_table;
|
||||
|
||||
native_set_pmd(&switcher_pmd, pfn_pmd(__pa(switcher_pte_page) >>
|
||||
PAGE_SHIFT, PAGE_KERNEL_EXEC));
|
||||
|
||||
pmd_table = __va(pgd_pfn(cpu->lg->
|
||||
pgdirs[cpu->cpu_pgd].pgdir[SWITCHER_PGD_INDEX])
|
||||
<< PAGE_SHIFT);
|
||||
native_set_pmd(&pmd_table[SWITCHER_PMD_INDEX], switcher_pmd);
|
||||
#else
|
||||
pgd_t switcher_pgd;
|
||||
|
||||
/* Make the last PGD entry for this Guest point to the Switcher's PTE
|
||||
* page for this CPU (with appropriate flags). */
|
||||
switcher_pgd = __pgd(__pa(switcher_pte_page) | __PAGE_KERNEL_EXEC);
|
||||
|
||||
cpu->lg->pgdirs[cpu->cpu_pgd].pgdir[SWITCHER_PGD_INDEX] = switcher_pgd;
|
||||
|
||||
#endif
|
||||
/* We also change the Switcher PTE page. When we're running the Guest,
|
||||
* we want the Guest's "regs" page to appear where the first Switcher
|
||||
* page for this CPU is. This is an optimization: when the Switcher
|
||||
|
|
|
|||
Reference in New Issue