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KVM: SVM: Don't save/restore host cr2 

The host never reads cr2 in process context, so are free to clobber it.  The
vmx code does this, so we can safely remove the save/restore code.

Signed-off-by: Avi Kivity <avi@redhat.com>
This commit is contained in:
Avi Kivity 2009-06-16 12:36:33 +03:00
parent d3edefc003
commit b3dbf89e67
1 changed files with 0 additions and 17 deletions
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17
arch/x86/kvm/svm.c
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@ -81,7 +81,6 @@ struct vcpu_svm {
u64 host_user_msrs[NR_HOST_SAVE_USER_MSRS];
u64 host_gs_base;
unsigned long host_cr2;
u32 *msrpm;
struct vmcb *hsave;
@ -186,19 +185,6 @@ static inline void invlpga(unsigned long addr, u32 asid)
asm volatile (__ex(SVM_INVLPGA) :: "a"(addr), "c"(asid));
}
static inline unsigned long kvm_read_cr2(void)
{
unsigned long cr2;
asm volatile ("mov %%cr2, %0" : "=r" (cr2));
return cr2;
}
static inline void kvm_write_cr2(unsigned long val)
{
asm volatile ("mov %0, %%cr2" :: "r" (val));
}
static inline void force_new_asid(struct kvm_vcpu *vcpu)
{
to_svm(vcpu)->asid_generation--;
@ -2527,7 +2513,6 @@ static void svm_vcpu_run(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)
fs_selector = kvm_read_fs();
gs_selector = kvm_read_gs();
ldt_selector = kvm_read_ldt();
svm->host_cr2 = kvm_read_cr2();
if (!is_nested(svm))
svm->vmcb->save.cr2 = vcpu->arch.cr2;
/* required for live migration with NPT */
@ -2614,8 +2599,6 @@ static void svm_vcpu_run(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)
vcpu->arch.regs[VCPU_REGS_RSP] = svm->vmcb->save.rsp;
vcpu->arch.regs[VCPU_REGS_RIP] = svm->vmcb->save.rip;
kvm_write_cr2(svm->host_cr2);
kvm_load_fs(fs_selector);
kvm_load_gs(gs_selector);
kvm_load_ldt(ldt_selector);