* [PATCH 4.14 STABLE 1/2] kvm: mmu: Don't read PDPTEs when paging is not enabled
2019-11-11 23:37 [PATCH 4.14 STABLE 0/2] KVM: x86: PAE related bug fixes Sean Christopherson
@ 2019-11-11 23:37 ` Sean Christopherson
2019-11-11 23:37 ` [PATCH 4.14 STABLE 2/2] KVM: x86: introduce is_pae_paging Sean Christopherson
2019-11-13 1:14 ` [PATCH 4.14 STABLE 0/2] KVM: x86: PAE related bug fixes Sasha Levin
2 siblings, 0 replies; 4+ messages in thread
From: Sean Christopherson @ 2019-11-11 23:37 UTC (permalink / raw)
To: stable, Greg Kroah-Hartman; +Cc: Paolo Bonzini, Junaid Shahid, linux-kernel
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;
}
--
2.24.0
^ permalink raw reply related [flat|nested] 4+ messages in thread* [PATCH 4.14 STABLE 2/2] KVM: x86: introduce is_pae_paging
2019-11-11 23:37 [PATCH 4.14 STABLE 0/2] KVM: x86: PAE related bug fixes Sean Christopherson
2019-11-11 23:37 ` [PATCH 4.14 STABLE 1/2] kvm: mmu: Don't read PDPTEs when paging is not enabled Sean Christopherson
@ 2019-11-11 23:37 ` Sean Christopherson
2019-11-13 1:14 ` [PATCH 4.14 STABLE 0/2] KVM: x86: PAE related bug fixes Sasha Levin
2 siblings, 0 replies; 4+ messages in thread
From: Sean Christopherson @ 2019-11-11 23:37 UTC (permalink / raw)
To: stable, Greg Kroah-Hartman; +Cc: Paolo Bonzini, Junaid Shahid, linux-kernel
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);
--
2.24.0
^ permalink raw reply related [flat|nested] 4+ messages in thread* Re: [PATCH 4.14 STABLE 0/2] KVM: x86: PAE related bug fixes
2019-11-11 23:37 [PATCH 4.14 STABLE 0/2] KVM: x86: PAE related bug fixes Sean Christopherson
2019-11-11 23:37 ` [PATCH 4.14 STABLE 1/2] kvm: mmu: Don't read PDPTEs when paging is not enabled Sean Christopherson
2019-11-11 23:37 ` [PATCH 4.14 STABLE 2/2] KVM: x86: introduce is_pae_paging Sean Christopherson
@ 2019-11-13 1:14 ` Sasha Levin
2 siblings, 0 replies; 4+ messages in thread
From: Sasha Levin @ 2019-11-13 1:14 UTC (permalink / raw)
To: Sean Christopherson
Cc: stable, Greg Kroah-Hartman, Paolo Bonzini, Junaid Shahid, linux-kernel
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.
--
Thanks,
Sasha
^ permalink raw reply [flat|nested] 4+ messages in thread