The primary goal is to land patch 2/2 (from Paolo), which fixes a reported crash when running 64-bit KVM guests on systems without unrestricted guest support.
Attempting to cherry-pick Paolo's patch revealed that a similar PAE bug fix from Junaid was also missing. Grab Junaid's patch as a prerequisite, even though it will effectively be overwritten, so that Paolo's upstream fix can be applied without modification (sans the vmx.c split in 5.x).
Junaid Shahid (1): kvm: mmu: Don't read PDPTEs when paging is not enabled
Paolo Bonzini (1): KVM: x86: introduce is_pae_paging
arch/x86/kvm/vmx.c | 7 +++---- arch/x86/kvm/x86.c | 8 ++++---- arch/x86/kvm/x86.h | 5 +++++ 3 files changed, 12 insertions(+), 8 deletions(-)
From: Junaid Shahid junaids@google.com
Upstream commit d35b34a9a70edae7ef923f100e51b8b5ae9fe899.
kvm should not attempt to read guest PDPTEs when CR0.PG = 0 and CR4.PAE = 1.
Signed-off-by: Junaid Shahid junaids@google.com Signed-off-by: Paolo Bonzini pbonzini@redhat.com Signed-off-by: Sean Christopherson sean.j.christopherson@intel.com --- arch/x86/kvm/x86.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 4927d0f5be13..801e7faba728 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -619,7 +619,7 @@ bool pdptrs_changed(struct kvm_vcpu *vcpu) gfn_t gfn; int r;
- if (is_long_mode(vcpu) || !is_pae(vcpu)) + if (is_long_mode(vcpu) || !is_pae(vcpu) || !is_paging(vcpu)) return false;
if (!test_bit(VCPU_EXREG_PDPTR, @@ -7751,7 +7751,7 @@ int kvm_arch_vcpu_ioctl_set_sregs(struct kvm_vcpu *vcpu, kvm_update_cpuid(vcpu);
idx = srcu_read_lock(&vcpu->kvm->srcu); - if (!is_long_mode(vcpu) && is_pae(vcpu)) { + if (!is_long_mode(vcpu) && is_pae(vcpu) && is_paging(vcpu)) { load_pdptrs(vcpu, vcpu->arch.walk_mmu, kvm_read_cr3(vcpu)); mmu_reset_needed = 1; }
From: Paolo Bonzini pbonzini@redhat.com
Upstream commit bf03d4f9334728bf7c8ffc7de787df48abd6340e.
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 --- arch/x86/kvm/vmx.c | 7 +++---- arch/x86/kvm/x86.c | 8 ++++---- arch/x86/kvm/x86.h | 5 +++++ 3 files changed, 12 insertions(+), 8 deletions(-)
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c index 02c0326dc259..532598637b24 100644 --- a/arch/x86/kvm/vmx.c +++ b/arch/x86/kvm/vmx.c @@ -4476,7 +4476,7 @@ 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]); @@ -4488,7 +4488,7 @@ 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); @@ -10914,8 +10914,7 @@ 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; diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 801e7faba728..ddab027a0370 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -619,7 +619,7 @@ 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, @@ -848,8 +848,8 @@ 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;
vcpu->arch.cr3 = cr3; @@ -7751,7 +7751,7 @@ int kvm_arch_vcpu_ioctl_set_sregs(struct kvm_vcpu *vcpu, 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; } diff --git a/arch/x86/kvm/x86.h b/arch/x86/kvm/x86.h index c88305d997b0..68eb0d03e5fc 100644 --- a/arch/x86/kvm/x86.h +++ b/arch/x86/kvm/x86.h @@ -94,6 +94,11 @@ 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);
On Mon, Nov 11, 2019 at 03:37:16PM -0800, Sean Christopherson wrote:
The primary goal is to land patch 2/2 (from Paolo), which fixes a reported crash when running 64-bit KVM guests on systems without unrestricted guest support.
Attempting to cherry-pick Paolo's patch revealed that a similar PAE bug fix from Junaid was also missing. Grab Junaid's patch as a prerequisite, even though it will effectively be overwritten, so that Paolo's upstream fix can be applied without modification (sans the vmx.c split in 5.x).
Junaid Shahid (1): kvm: mmu: Don't read PDPTEs when paging is not enabled
Paolo Bonzini (1): KVM: x86: introduce is_pae_paging
arch/x86/kvm/vmx.c | 7 +++---- arch/x86/kvm/x86.c | 8 ++++---- arch/x86/kvm/x86.h | 5 +++++ 3 files changed, 12 insertions(+), 8 deletions(-)
Queued up for 4.14, thank you.
linux-stable-mirror@lists.linaro.org
-
Sasha Levin -
Sean Christopherson