Few patches were recently marked for stable@ but commits are not backportable as-is and require a few tweaks. Here is 5.1 stable backport.
[PATCH2 of the series applies as-is, I have it here for completeness]
Jan Kiszka (1): KVM: nVMX: Clear pending KVM_REQ_GET_VMCS12_PAGES when leaving nested
Paolo Bonzini (2): KVM: nVMX: do not use dangling shadow VMCS after guest reset Revert "kvm: x86: Use task structs fpu field for user"
arch/x86/include/asm/kvm_host.h | 7 ++++--- arch/x86/kvm/vmx/nested.c | 10 +++++++++- arch/x86/kvm/x86.c | 4 ++-- 3 files changed, 15 insertions(+), 6 deletions(-)
From: Paolo Bonzini pbonzini@redhat.com
[ Upstream commit 88dddc11a8d6b09201b4db9d255b3394d9bc9e57 ]
If a KVM guest is reset while running a nested guest, free_nested will disable the shadow VMCS execution control in the vmcs01. However, on the next KVM_RUN vmx_vcpu_run would nevertheless try to sync the VMCS12 to the shadow VMCS which has since been freed.
This causes a vmptrld of a NULL pointer on my machime, but Jan reports the host to hang altogether. Let's see how much this trivial patch fixes.
Reported-by: Jan Kiszka jan.kiszka@siemens.com Cc: Liran Alon liran.alon@oracle.com Cc: stable@vger.kernel.org Signed-off-by: Paolo Bonzini pbonzini@redhat.com --- arch/x86/kvm/vmx/nested.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-)
diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c index 4ca834d22169..3f48006a43ec 100644 --- a/arch/x86/kvm/vmx/nested.c +++ b/arch/x86/kvm/vmx/nested.c @@ -184,6 +184,7 @@ static void vmx_disable_shadow_vmcs(struct vcpu_vmx *vmx) { vmcs_clear_bits(SECONDARY_VM_EXEC_CONTROL, SECONDARY_EXEC_SHADOW_VMCS); vmcs_write64(VMCS_LINK_POINTER, -1ull); + vmx->nested.need_vmcs12_sync = false; }
static inline void nested_release_evmcs(struct kvm_vcpu *vcpu) @@ -1328,6 +1329,9 @@ static void copy_shadow_to_vmcs12(struct vcpu_vmx *vmx) u64 field_value; struct vmcs *shadow_vmcs = vmx->vmcs01.shadow_vmcs;
+ if (WARN_ON(!shadow_vmcs)) + return; + preempt_disable();
vmcs_load(shadow_vmcs); @@ -1366,6 +1370,9 @@ static void copy_vmcs12_to_shadow(struct vcpu_vmx *vmx) u64 field_value = 0; struct vmcs *shadow_vmcs = vmx->vmcs01.shadow_vmcs;
+ if (WARN_ON(!shadow_vmcs)) + return; + vmcs_load(shadow_vmcs);
for (q = 0; q < ARRAY_SIZE(fields); q++) { @@ -4340,7 +4347,6 @@ static inline void nested_release_vmcs12(struct kvm_vcpu *vcpu) /* copy to memory all shadowed fields in case they were modified */ copy_shadow_to_vmcs12(vmx); - vmx->nested.need_vmcs12_sync = false; vmx_disable_shadow_vmcs(vmx); } vmx->nested.posted_intr_nv = -1;
From: Jan Kiszka jan.kiszka@siemens.com
[ Upstream commit cf64527bb33f6cec2ed50f89182fc4688d0056b6 ]
Letting this pend may cause nested_get_vmcs12_pages to run against an invalid state, corrupting the effective vmcs of L1.
This was triggerable in QEMU after a guest corruption in L2, followed by a L1 reset.
Signed-off-by: Jan Kiszka jan.kiszka@siemens.com Reviewed-by: Liran Alon liran.alon@oracle.com Cc: stable@vger.kernel.org Fixes: 7f7f1ba33cf2 ("KVM: x86: do not load vmcs12 pages while still in SMM") Signed-off-by: Paolo Bonzini pbonzini@redhat.com --- arch/x86/kvm/vmx/nested.c | 2 ++ 1 file changed, 2 insertions(+)
diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c index 3f48006a43ec..f78975d4a7fa 100644 --- a/arch/x86/kvm/vmx/nested.c +++ b/arch/x86/kvm/vmx/nested.c @@ -212,6 +212,8 @@ static void free_nested(struct kvm_vcpu *vcpu) if (!vmx->nested.vmxon && !vmx->nested.smm.vmxon) return;
+ kvm_clear_request(KVM_REQ_GET_VMCS12_PAGES, vcpu); + vmx->nested.vmxon = false; vmx->nested.smm.vmxon = false; free_vpid(vmx->nested.vpid02);
From: Paolo Bonzini pbonzini@redhat.com
[ Upstream commit ec269475cba7bcdd1eb8fdf8e87f4c6c81a376fe ]
This reverts commit 240c35a3783ab9b3a0afaba0dde7291295680a6b ("kvm: x86: Use task structs fpu field for user", 2018-11-06). The commit is broken and causes QEMU's FPU state to be destroyed when KVM_RUN is preempted.
Fixes: 240c35a3783a ("kvm: x86: Use task structs fpu field for user") Cc: stable@vger.kernel.org Signed-off-by: Paolo Bonzini pbonzini@redhat.com --- arch/x86/include/asm/kvm_host.h | 7 ++++--- arch/x86/kvm/x86.c | 4 ++-- 2 files changed, 6 insertions(+), 5 deletions(-)
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h index c79abe7ca093..564729a4a25c 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -609,15 +609,16 @@ struct kvm_vcpu_arch {
/* * QEMU userspace and the guest each have their own FPU state. - * In vcpu_run, we switch between the user, maintained in the - * task_struct struct, and guest FPU contexts. While running a VCPU, - * the VCPU thread will have the guest FPU context. + * In vcpu_run, we switch between the user and guest FPU contexts. + * While running a VCPU, the VCPU thread will have the guest FPU + * context. * * Note that while the PKRU state lives inside the fpu registers, * it is switched out separately at VMENTER and VMEXIT time. The * "guest_fpu" state here contains the guest FPU context, with the * host PRKU bits. */ + struct fpu user_fpu; struct fpu *guest_fpu;
u64 xcr0; diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 37028ea85d4c..aede8fa2ea9a 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -8172,7 +8172,7 @@ static int complete_emulated_mmio(struct kvm_vcpu *vcpu) static void kvm_load_guest_fpu(struct kvm_vcpu *vcpu) { preempt_disable(); - copy_fpregs_to_fpstate(¤t->thread.fpu); + copy_fpregs_to_fpstate(&vcpu->arch.user_fpu); /* PKRU is separately restored in kvm_x86_ops->run. */ __copy_kernel_to_fpregs(&vcpu->arch.guest_fpu->state, ~XFEATURE_MASK_PKRU); @@ -8185,7 +8185,7 @@ static void kvm_put_guest_fpu(struct kvm_vcpu *vcpu) { preempt_disable(); copy_fpregs_to_fpstate(vcpu->arch.guest_fpu); - copy_kernel_to_fpregs(¤t->thread.fpu.state); + copy_kernel_to_fpregs(&vcpu->arch.user_fpu.state); preempt_enable(); ++vcpu->stat.fpu_reload; trace_kvm_fpu(0);
On 25/07/19 13:49, Vitaly Kuznetsov wrote:
Few patches were recently marked for stable@ but commits are not backportable as-is and require a few tweaks. Here is 5.1 stable backport.
[PATCH2 of the series applies as-is, I have it here for completeness]
Jan Kiszka (1): KVM: nVMX: Clear pending KVM_REQ_GET_VMCS12_PAGES when leaving nested
Paolo Bonzini (2): KVM: nVMX: do not use dangling shadow VMCS after guest reset Revert "kvm: x86: Use task structs fpu field for user"
arch/x86/include/asm/kvm_host.h | 7 ++++--- arch/x86/kvm/vmx/nested.c | 10 +++++++++- arch/x86/kvm/x86.c | 4 ++-- 3 files changed, 15 insertions(+), 6 deletions(-)
Acked-by: Paolo Bonzini pbonzini@redhat.com
On Thu, Jul 25, 2019 at 01:49:35PM +0200, Vitaly Kuznetsov wrote:
Few patches were recently marked for stable@ but commits are not backportable as-is and require a few tweaks. Here is 5.1 stable backport.
[PATCH2 of the series applies as-is, I have it here for completeness]
Jan Kiszka (1): KVM: nVMX: Clear pending KVM_REQ_GET_VMCS12_PAGES when leaving nested
Paolo Bonzini (2): KVM: nVMX: do not use dangling shadow VMCS after guest reset Revert "kvm: x86: Use task structs fpu field for user"
All now applied, thanks!
greg k-h
linux-stable-mirror@lists.linaro.org
-
Greg KH -
Paolo Bonzini -
Vitaly Kuznetsov