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KVM: x86: introduce is_pae_paging

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[ Upstream commit bf03d4f933 ]

Checking for 32-bit PAE is quite common around code that fiddles with
the PDPTRs.  Add a function to compress all checks into a single
invocation.

Moving to the common helper also fixes a subtle bug in kvm_set_cr3()
where it fails to check is_long_mode() and results in KVM incorrectly
attempting to load PDPTRs for a 64-bit guest.

Reviewed-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
[sean: backport to 4.x; handle vmx.c split in 5.x, call out the bugfix]
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Tested-by: Thomas Lamprecht <t.lamprecht@proxmox.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Paolo Bonzini 2019-11-11 14:54:23 -08:00 committed by Greg Kroah-Hartman
parent c555efaf14
commit dbf1ef2dc0
3 changed files with 12 additions and 8 deletions
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7
arch/x86/kvm/vmx.c
View file

@ -5173,7 +5173,7 @@ static void ept_load_pdptrs(struct kvm_vcpu *vcpu)
(unsigned long *)&vcpu->arch.regs_dirty))
return;
if (is_paging(vcpu) && is_pae(vcpu) && !is_long_mode(vcpu)) {
if (is_pae_paging(vcpu)) {
vmcs_write64(GUEST_PDPTR0, mmu->pdptrs[0]);
vmcs_write64(GUEST_PDPTR1, mmu->pdptrs[1]);
vmcs_write64(GUEST_PDPTR2, mmu->pdptrs[2]);
@ -5185,7 +5185,7 @@ static void ept_save_pdptrs(struct kvm_vcpu *vcpu)
{
struct kvm_mmu *mmu = vcpu->arch.walk_mmu;
if (is_paging(vcpu) && is_pae(vcpu) && !is_long_mode(vcpu)) {
if (is_pae_paging(vcpu)) {
mmu->pdptrs[0] = vmcs_read64(GUEST_PDPTR0);
mmu->pdptrs[1] = vmcs_read64(GUEST_PDPTR1);
mmu->pdptrs[2] = vmcs_read64(GUEST_PDPTR2);
@ -12013,8 +12013,7 @@ static int nested_vmx_load_cr3(struct kvm_vcpu *vcpu, unsigned long cr3, bool ne
* If PAE paging and EPT are both on, CR3 is not used by the CPU and
* must not be dereferenced.
*/
if (!is_long_mode(vcpu) && is_pae(vcpu) && is_paging(vcpu) &&
!nested_ept) {
if (is_pae_paging(vcpu) && !nested_ept) {
if (!load_pdptrs(vcpu, vcpu->arch.walk_mmu, cr3)) {
*entry_failure_code = ENTRY_FAIL_PDPTE;
return 1;

8
arch/x86/kvm/x86.c
View file

@ -634,7 +634,7 @@ bool pdptrs_changed(struct kvm_vcpu *vcpu)
gfn_t gfn;
int r;
if (is_long_mode(vcpu) || !is_pae(vcpu) || !is_paging(vcpu))
if (!is_pae_paging(vcpu))
return false;
if (!test_bit(VCPU_EXREG_PDPTR,
@ -885,8 +885,8 @@ int kvm_set_cr3(struct kvm_vcpu *vcpu, unsigned long cr3)
if (is_long_mode(vcpu) &&
(cr3 & rsvd_bits(cpuid_maxphyaddr(vcpu), 63)))
return 1;
else if (is_pae(vcpu) && is_paging(vcpu) &&
!load_pdptrs(vcpu, vcpu->arch.walk_mmu, cr3))
else if (is_pae_paging(vcpu) &&
!load_pdptrs(vcpu, vcpu->arch.walk_mmu, cr3))
return 1;
kvm_mmu_new_cr3(vcpu, cr3, skip_tlb_flush);
@ -8348,7 +8348,7 @@ static int __set_sregs(struct kvm_vcpu *vcpu, struct kvm_sregs *sregs)
kvm_update_cpuid(vcpu);
idx = srcu_read_lock(&vcpu->kvm->srcu);
if (!is_long_mode(vcpu) && is_pae(vcpu) && is_paging(vcpu)) {
if (is_pae_paging(vcpu)) {
load_pdptrs(vcpu, vcpu->arch.walk_mmu, kvm_read_cr3(vcpu));
mmu_reset_needed = 1;
}

5
arch/x86/kvm/x86.h
View file

@ -139,6 +139,11 @@ static inline int is_paging(struct kvm_vcpu *vcpu)
return likely(kvm_read_cr0_bits(vcpu, X86_CR0_PG));
}
static inline bool is_pae_paging(struct kvm_vcpu *vcpu)
{
return !is_long_mode(vcpu) && is_pae(vcpu) && is_paging(vcpu);
}
static inline u32 bit(int bitno)
{
return 1 << (bitno & 31);