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KVM: x86/mmu: Move fast_cr3_switch() side effects to __kvm_mmu_new_cr3()

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Handle the side effects of a fast CR3 (PGD) switch up a level in
__kvm_mmu_new_cr3(), which is the only caller of fast_cr3_switch().

This consolidates handling all side effects in __kvm_mmu_new_cr3()
(where freeing the current root when KVM can't do a fast switch is
already handled), and ameliorates the pain of adding a second boolean in
a future patch to provide a separate "skip" override for the MMU sync.

Cc: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Message-Id: <20200320212833.3507-31-sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Sean Christopherson 2020-03-20 14:28:26 -07:00 committed by Paolo Bonzini
parent 4de1f9d469
commit b869855bad
1 changed files with 31 additions and 38 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

69
arch/x86/kvm/mmu/mmu.c
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@ -4284,8 +4284,7 @@ static bool cached_root_available(struct kvm_vcpu *vcpu, gpa_t new_cr3,
}
static bool fast_cr3_switch(struct kvm_vcpu *vcpu, gpa_t new_cr3,
union kvm_mmu_page_role new_role,
bool skip_tlb_flush)
union kvm_mmu_page_role new_role)
{
struct kvm_mmu *mmu = vcpu->arch.mmu;
@ -4295,39 +4294,9 @@ static bool fast_cr3_switch(struct kvm_vcpu *vcpu, gpa_t new_cr3,
* later if necessary.
*/
if (mmu->shadow_root_level >= PT64_ROOT_4LEVEL &&
mmu->root_level >= PT64_ROOT_4LEVEL) {
if (mmu_check_root(vcpu, new_cr3 >> PAGE_SHIFT))
return false;
if (cached_root_available(vcpu, new_cr3, new_role)) {
/*
* It is possible that the cached previous root page is
* obsolete because of a change in the MMU generation
* number. However, changing the generation number is
* accompanied by KVM_REQ_MMU_RELOAD, which will free
* the root set here and allocate a new one.
*/
kvm_make_request(KVM_REQ_LOAD_MMU_PGD, vcpu);
if (!skip_tlb_flush) {
kvm_make_request(KVM_REQ_MMU_SYNC, vcpu);
kvm_make_request(KVM_REQ_TLB_FLUSH_CURRENT, vcpu);
}
/*
* The last MMIO access's GVA and GPA are cached in the
* VCPU. When switching to a new CR3, that GVA->GPA
* mapping may no longer be valid. So clear any cached
* MMIO info even when we don't need to sync the shadow
* page tables.
*/
vcpu_clear_mmio_info(vcpu, MMIO_GVA_ANY);
__clear_sp_write_flooding_count(
page_header(mmu->root_hpa));
return true;
}
}
mmu->root_level >= PT64_ROOT_4LEVEL)
return !mmu_check_root(vcpu, new_cr3 >> PAGE_SHIFT) &&
cached_root_available(vcpu, new_cr3, new_role);
return false;
}
@ -4336,9 +4305,33 @@ static void __kvm_mmu_new_cr3(struct kvm_vcpu *vcpu, gpa_t new_cr3,
union kvm_mmu_page_role new_role,
bool skip_tlb_flush)
{
if (!fast_cr3_switch(vcpu, new_cr3, new_role, skip_tlb_flush))
kvm_mmu_free_roots(vcpu, vcpu->arch.mmu,
KVM_MMU_ROOT_CURRENT);
if (!fast_cr3_switch(vcpu, new_cr3, new_role)) {
kvm_mmu_free_roots(vcpu, vcpu->arch.mmu, KVM_MMU_ROOT_CURRENT);
return;
}
/*
* It's possible that the cached previous root page is obsolete because
* of a change in the MMU generation number. However, changing the
* generation number is accompanied by KVM_REQ_MMU_RELOAD, which will
* free the root set here and allocate a new one.
*/
kvm_make_request(KVM_REQ_LOAD_MMU_PGD, vcpu);
if (!skip_tlb_flush) {
kvm_make_request(KVM_REQ_MMU_SYNC, vcpu);
kvm_make_request(KVM_REQ_TLB_FLUSH_CURRENT, vcpu);
}
/*
* The last MMIO access's GVA and GPA are cached in the VCPU. When
* switching to a new CR3, that GVA->GPA mapping may no longer be
* valid. So clear any cached MMIO info even when we don't need to sync
* the shadow page tables.
*/
vcpu_clear_mmio_info(vcpu, MMIO_GVA_ANY);
__clear_sp_write_flooding_count(page_header(vcpu->arch.mmu->root_hpa));
}
void kvm_mmu_new_cr3(struct kvm_vcpu *vcpu, gpa_t new_cr3, bool skip_tlb_flush)