The patch below does not apply to the 5.8-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 2ba4493a8b195cc1d7dd5b762a84e6235c2d67bd Mon Sep 17 00:00:00 2001
From: Sean Christopherson sean.j.christopherson@intel.com Date: Wed, 23 Sep 2020 11:44:48 -0700 Subject: [PATCH] KVM: nVMX: Explicitly check for valid guest state for !unrestricted guest
Call guest_state_valid() directly instead of querying emulation_required when checking if L1 is attempting VM-Enter with invalid guest state. If emulate_invalid_guest_state is false, KVM will fixup segment regs to avoid emulation and will never set emulation_required, i.e. KVM will incorrectly miss the associated consistency checks because the nested path stuffs segments directly into vmcs02.
Opportunsitically add Consistency Check tracing to make future debug suck a little less.
Fixes: 2bb8cafea80bf ("KVM: vVMX: signal failure for nested VMEntry if emulation_required") Fixes: 3184a995f782c ("KVM: nVMX: fix vmentry failure code when L2 state would require emulation") Cc: stable@vger.kernel.org Signed-off-by: Sean Christopherson sean.j.christopherson@intel.com Message-Id: 20200923184452.980-4-sean.j.christopherson@intel.com Signed-off-by: Paolo Bonzini pbonzini@redhat.com
diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c index 321a6790ad9f..e004ab8c2ea6 100644 --- a/arch/x86/kvm/vmx/nested.c +++ b/arch/x86/kvm/vmx/nested.c @@ -2576,7 +2576,7 @@ static int prepare_vmcs02(struct kvm_vcpu *vcpu, struct vmcs12 *vmcs12, * which means L1 attempted VMEntry to L2 with invalid state. * Fail the VMEntry. */ - if (vmx->emulation_required) { + if (CC(!vmx_guest_state_valid(vcpu))) { *entry_failure_code = ENTRY_FAIL_DEFAULT; return -EINVAL; } diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c index 68b9a9b3661c..d87c8d2892ca 100644 --- a/arch/x86/kvm/vmx/vmx.c +++ b/arch/x86/kvm/vmx/vmx.c @@ -337,7 +337,6 @@ static const struct kernel_param_ops vmentry_l1d_flush_ops = { }; module_param_cb(vmentry_l1d_flush, &vmentry_l1d_flush_ops, NULL, 0644);
-static bool guest_state_valid(struct kvm_vcpu *vcpu); static u32 vmx_segment_access_rights(struct kvm_segment *var); static __always_inline void vmx_disable_intercept_for_msr(unsigned long *msr_bitmap, u32 msr, int type); @@ -1340,7 +1339,7 @@ static void vmx_vcpu_put(struct kvm_vcpu *vcpu)
static bool emulation_required(struct kvm_vcpu *vcpu) { - return emulate_invalid_guest_state && !guest_state_valid(vcpu); + return emulate_invalid_guest_state && !vmx_guest_state_valid(vcpu); }
unsigned long vmx_get_rflags(struct kvm_vcpu *vcpu) @@ -3402,11 +3401,8 @@ static bool cs_ss_rpl_check(struct kvm_vcpu *vcpu) * not. * We assume that registers are always usable */ -static bool guest_state_valid(struct kvm_vcpu *vcpu) +bool __vmx_guest_state_valid(struct kvm_vcpu *vcpu) { - if (is_unrestricted_guest(vcpu)) - return true; - /* real mode guest state checks */ if (!is_protmode(vcpu) || (vmx_get_rflags(vcpu) & X86_EFLAGS_VM)) { if (!rmode_segment_valid(vcpu, VCPU_SREG_CS)) diff --git a/arch/x86/kvm/vmx/vmx.h b/arch/x86/kvm/vmx/vmx.h index 60bb7a125f0b..e87fae204d3d 100644 --- a/arch/x86/kvm/vmx/vmx.h +++ b/arch/x86/kvm/vmx/vmx.h @@ -321,6 +321,7 @@ void vmx_get_segment(struct kvm_vcpu *vcpu, struct kvm_segment *var, int seg); void vmx_set_segment(struct kvm_vcpu *vcpu, struct kvm_segment *var, int seg); u64 construct_eptp(struct kvm_vcpu *vcpu, unsigned long root_hpa, int root_level); + void update_exception_bitmap(struct kvm_vcpu *vcpu); void vmx_update_msr_bitmap(struct kvm_vcpu *vcpu); bool vmx_nmi_blocked(struct kvm_vcpu *vcpu); @@ -472,6 +473,12 @@ static inline bool is_unrestricted_guest(struct kvm_vcpu *vcpu) SECONDARY_EXEC_UNRESTRICTED_GUEST)); }
+bool __vmx_guest_state_valid(struct kvm_vcpu *vcpu); +static inline bool vmx_guest_state_valid(struct kvm_vcpu *vcpu) +{ + return is_unrestricted_guest(vcpu) || __vmx_guest_state_valid(vcpu); +} + void dump_vmcs(void);
#endif /* __KVM_X86_VMX_H */