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KVM: MMU: stop dereferencing vcpu->arch.mmu to get the context for MM…
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…U init

kvm_init_shadow_mmu() was actually the only function that could be called
with different vcpu->arch.mmu values.  Now that kvm_init_shadow_npt_mmu()
is separated from kvm_init_shadow_mmu(), we always know the MMU context
we need to use and there is no need to dereference vcpu->arch.mmu pointer.

Based on a patch by Vitaly Kuznetsov <vkuznets@redhat.com>.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Message-Id: <20200710141157.1640173-3-vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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Paolo Bonzini committed Jul 10, 2020
1 parent 0f04a2a commit 8c00865
Showing 1 changed file with 10 additions and 11 deletions.
21 changes: 10 additions & 11 deletions arch/x86/kvm/mmu/mmu.c
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Original file line number Diff line number Diff line change
Expand Up @@ -4850,7 +4850,7 @@ kvm_calc_tdp_mmu_root_page_role(struct kvm_vcpu *vcpu, bool base_only)

static void init_kvm_tdp_mmu(struct kvm_vcpu *vcpu)
{
struct kvm_mmu *context = vcpu->arch.mmu;
struct kvm_mmu *context = &vcpu->arch.root_mmu;
union kvm_mmu_role new_role =
kvm_calc_tdp_mmu_root_page_role(vcpu, false);

Expand Down Expand Up @@ -4918,11 +4918,10 @@ kvm_calc_shadow_mmu_root_page_role(struct kvm_vcpu *vcpu, bool base_only)
return role;
}

static void shadow_mmu_init_context(struct kvm_vcpu *vcpu, u32 cr0, u32 cr4,
u32 efer, union kvm_mmu_role new_role)
static void shadow_mmu_init_context(struct kvm_vcpu *vcpu, struct kvm_mmu *context,
u32 cr0, u32 cr4, u32 efer,
union kvm_mmu_role new_role)
{
struct kvm_mmu *context = vcpu->arch.mmu;

if (!(cr0 & X86_CR0_PG))
nonpaging_init_context(vcpu, context);
else if (efer & EFER_LMA)
Expand All @@ -4938,23 +4937,23 @@ static void shadow_mmu_init_context(struct kvm_vcpu *vcpu, u32 cr0, u32 cr4,

static void kvm_init_shadow_mmu(struct kvm_vcpu *vcpu, u32 cr0, u32 cr4, u32 efer)
{
struct kvm_mmu *context = vcpu->arch.mmu;
struct kvm_mmu *context = &vcpu->arch.root_mmu;
union kvm_mmu_role new_role =
kvm_calc_shadow_mmu_root_page_role(vcpu, false);

if (new_role.as_u64 != context->mmu_role.as_u64)
shadow_mmu_init_context(vcpu, cr0, cr4, efer, new_role);
shadow_mmu_init_context(vcpu, context, cr0, cr4, efer, new_role);
}

void kvm_init_shadow_npt_mmu(struct kvm_vcpu *vcpu, u32 cr0, u32 cr4, u32 efer,
gpa_t nested_cr3)
{
struct kvm_mmu *context = vcpu->arch.mmu;
struct kvm_mmu *context = &vcpu->arch.guest_mmu;
union kvm_mmu_role new_role =
kvm_calc_shadow_mmu_root_page_role(vcpu, false);

if (new_role.as_u64 != context->mmu_role.as_u64)
shadow_mmu_init_context(vcpu, cr0, cr4, efer, new_role);
shadow_mmu_init_context(vcpu, context, cr0, cr4, efer, new_role);
}
EXPORT_SYMBOL_GPL(kvm_init_shadow_npt_mmu);

Expand Down Expand Up @@ -4990,7 +4989,7 @@ kvm_calc_shadow_ept_root_page_role(struct kvm_vcpu *vcpu, bool accessed_dirty,
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;
struct kvm_mmu *context = &vcpu->arch.guest_mmu;
u8 level = vmx_eptp_page_walk_level(new_eptp);
union kvm_mmu_role new_role =
kvm_calc_shadow_ept_root_page_role(vcpu, accessed_dirty,
Expand Down Expand Up @@ -5024,7 +5023,7 @@ EXPORT_SYMBOL_GPL(kvm_init_shadow_ept_mmu);

static void init_kvm_softmmu(struct kvm_vcpu *vcpu)
{
struct kvm_mmu *context = vcpu->arch.mmu;
struct kvm_mmu *context = &vcpu->arch.root_mmu;

kvm_init_shadow_mmu(vcpu,
kvm_read_cr0_bits(vcpu, X86_CR0_PG),
Expand Down

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