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x86/kvm/nVMX: introduce source data cache for kvm_init_shadow_ept_mmu()

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MMU re-initialization is expensive, in particular,
update_permission_bitmask() and update_pkru_bitmask() are.

Cache the data used to setup shadow EPT MMU and avoid full re-init when
it is unchanged.

Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Vitaly Kuznetsov 2018-10-08 21:28:11 +02:00 committed by Paolo Bonzini
parent 36d9594dfb
commit a336282d77
2 changed files with 52 additions and 15 deletions
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14
arch/x86/include/asm/kvm_host.h
View File

@ -283,7 +283,21 @@ union kvm_mmu_page_role {
};
union kvm_mmu_extended_role {
/*
* This structure complements kvm_mmu_page_role caching everything needed for
* MMU configuration. If nothing in both these structures changed, MMU
* re-configuration can be skipped. @valid bit is set on first usage so we don't
* treat all-zero structure as valid data.
*/
u32 word;
struct {
unsigned int valid:1;
unsigned int execonly:1;
unsigned int cr4_pse:1;
unsigned int cr4_pke:1;
unsigned int cr4_smap:1;
unsigned int cr4_smep:1;
};
};
union kvm_mmu_role {

53
arch/x86/kvm/mmu.c
View File

@ -4724,6 +4724,20 @@ static void paging32E_init_context(struct kvm_vcpu *vcpu,
paging64_init_context_common(vcpu, context, PT32E_ROOT_LEVEL);
}
static union kvm_mmu_extended_role kvm_calc_mmu_role_ext(struct kvm_vcpu *vcpu)
{
union kvm_mmu_extended_role ext = {0};
ext.cr4_smep = !!kvm_read_cr4_bits(vcpu, X86_CR4_SMEP);
ext.cr4_smap = !!kvm_read_cr4_bits(vcpu, X86_CR4_SMAP);
ext.cr4_pse = !!is_pse(vcpu);
ext.cr4_pke = !!kvm_read_cr4_bits(vcpu, X86_CR4_PKE);
ext.valid = 1;
return ext;
}
static union kvm_mmu_page_role
kvm_calc_tdp_mmu_root_page_role(struct kvm_vcpu *vcpu)
{
@ -4830,19 +4844,23 @@ void kvm_init_shadow_mmu(struct kvm_vcpu *vcpu)
}
EXPORT_SYMBOL_GPL(kvm_init_shadow_mmu);
static union kvm_mmu_page_role
kvm_calc_shadow_ept_root_page_role(struct kvm_vcpu *vcpu, bool accessed_dirty)
static union kvm_mmu_role
kvm_calc_shadow_ept_root_page_role(struct kvm_vcpu *vcpu, bool accessed_dirty,
bool execonly)
{
union kvm_mmu_page_role role;
union kvm_mmu_role role;
/* Role is inherited from root_mmu */
role.word = vcpu->arch.root_mmu.base_role.word;
/* Base role is inherited from root_mmu */
role.base.word = vcpu->arch.root_mmu.mmu_role.base.word;
role.ext = kvm_calc_mmu_role_ext(vcpu);
role.level = PT64_ROOT_4LEVEL;
role.direct = false;
role.ad_disabled = !accessed_dirty;
role.guest_mode = true;
role.access = ACC_ALL;
role.base.level = PT64_ROOT_4LEVEL;
role.base.direct = false;
role.base.ad_disabled = !accessed_dirty;
role.base.guest_mode = true;
role.base.access = ACC_ALL;
role.ext.execonly = execonly;
return role;
}
@ -4851,10 +4869,16 @@ void kvm_init_shadow_ept_mmu(struct kvm_vcpu *vcpu, bool execonly,
bool accessed_dirty, gpa_t new_eptp)
{
struct kvm_mmu *context = vcpu->arch.mmu;
union kvm_mmu_page_role root_page_role =
kvm_calc_shadow_ept_root_page_role(vcpu, accessed_dirty);
union kvm_mmu_role new_role =
kvm_calc_shadow_ept_root_page_role(vcpu, accessed_dirty,
execonly);
__kvm_mmu_new_cr3(vcpu, new_eptp, new_role.base, false);
new_role.base.word &= mmu_base_role_mask.word;
if (new_role.as_u64 == context->mmu_role.as_u64)
return;
__kvm_mmu_new_cr3(vcpu, new_eptp, root_page_role, false);
context->shadow_root_level = PT64_ROOT_4LEVEL;
context->nx = true;
@ -4866,8 +4890,7 @@ void kvm_init_shadow_ept_mmu(struct kvm_vcpu *vcpu, bool execonly,
context->update_pte = ept_update_pte;
context->root_level = PT64_ROOT_4LEVEL;
context->direct_map = false;
context->mmu_role.base.word =
root_page_role.word & mmu_base_role_mask.word;
context->mmu_role.as_u64 = new_role.as_u64;
update_permission_bitmask(vcpu, context, true);
update_pkru_bitmask(vcpu, context, true);