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KVM: VMX: conditionally disable 2M pages 

Disable usage of 2M pages if VMX_EPT_2MB_PAGE_BIT (bit 16) is clear
in MSR_IA32_VMX_EPT_VPID_CAP and EPT is enabled.

[avi: s/largepages_disabled/largepages_enabled/ to avoid negative logic]

Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
This commit is contained in:
Marcelo Tosatti 2009-06-11 12:07:44 -03:00 committed by Avi Kivity
parent 68f89400bc
commit 54dee9933e
3 changed files with 16 additions and 2 deletions
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3
arch/x86/kvm/vmx.c
View File

@ -1381,6 +1381,9 @@ static __init int hardware_setup(void)
if (!cpu_has_vmx_tpr_shadow())
kvm_x86_ops->update_cr8_intercept = NULL;
if (enable_ept && !cpu_has_vmx_ept_2m_page())
kvm_disable_largepages();
return alloc_kvm_area();
}

1
include/linux/kvm_host.h
View File

@ -224,6 +224,7 @@ int kvm_arch_set_memory_region(struct kvm *kvm,
struct kvm_userspace_memory_region *mem,
struct kvm_memory_slot old,
int user_alloc);
void kvm_disable_largepages(void);
void kvm_arch_flush_shadow(struct kvm *kvm);
gfn_t unalias_gfn(struct kvm *kvm, gfn_t gfn);
struct page *gfn_to_page(struct kvm *kvm, gfn_t gfn);

14
virt/kvm/kvm_main.c
View File

@ -85,6 +85,8 @@ static long kvm_vcpu_ioctl(struct file *file, unsigned int ioctl,
static bool kvm_rebooting;
static bool largepages_enabled = true;
#ifdef KVM_CAP_DEVICE_ASSIGNMENT
static struct kvm_assigned_dev_kernel *kvm_find_assigned_dev(struct list_head *head,
int assigned_dev_id)
@ -1174,9 +1176,11 @@ int __kvm_set_memory_region(struct kvm *kvm,
ugfn = new.userspace_addr >> PAGE_SHIFT;
/*
* If the gfn and userspace address are not aligned wrt each
* other, disable large page support for this slot
* other, or if explicitly asked to, disable large page
* support for this slot
*/
if ((base_gfn ^ ugfn) & (KVM_PAGES_PER_HPAGE - 1))
if ((base_gfn ^ ugfn) & (KVM_PAGES_PER_HPAGE - 1) ||
!largepages_enabled)
for (i = 0; i < largepages; ++i)
new.lpage_info[i].write_count = 1;
}
@ -1291,6 +1295,12 @@ out:
return r;
}
void kvm_disable_largepages(void)
{
largepages_enabled = false;
}
EXPORT_SYMBOL_GPL(kvm_disable_largepages);
int is_error_page(struct page *page)
{
return page == bad_page;