From: Sean Christopherson sean.j.christopherson@intel.com
[ Upstream commit c2fe3cd4604ac87c587db05d41843d667dc43815 ]
Split out VMX's checks on CR4.VMXE to a dedicated hook, .is_valid_cr4(), and invoke the new hook from kvm_valid_cr4(). This fixes an issue where KVM_SET_SREGS would return success while failing to actually set CR4.
Fixing the issue by explicitly checking kvm_x86_ops.set_cr4()'s return in __set_sregs() is not a viable option as KVM has already stuffed a variety of vCPU state.
Note, kvm_valid_cr4() and is_valid_cr4() have different return types and inverted semantics. This will be remedied in a future patch.
Fixes: 5e1746d6205d ("KVM: nVMX: Allow setting the VMXE bit in CR4") Signed-off-by: Sean Christopherson sean.j.christopherson@intel.com Message-Id: 20201007014417.29276-5-sean.j.christopherson@intel.com Signed-off-by: Paolo Bonzini pbonzini@redhat.com Signed-off-by: Sasha Levin sashal@kernel.org --- arch/x86/include/asm/kvm_host.h | 3 ++- arch/x86/kvm/svm/svm.c | 9 +++++++-- arch/x86/kvm/svm/svm.h | 2 +- arch/x86/kvm/vmx/nested.c | 2 +- arch/x86/kvm/vmx/vmx.c | 31 ++++++++++++++++++------------- arch/x86/kvm/vmx/vmx.h | 2 +- arch/x86/kvm/x86.c | 6 ++++-- 7 files changed, 34 insertions(+), 21 deletions(-)
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h index 94fbbdb888cf..87c13ef4ee8e 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -1117,7 +1117,8 @@ struct kvm_x86_ops { struct kvm_segment *var, int seg); void (*get_cs_db_l_bits)(struct kvm_vcpu *vcpu, int *db, int *l); void (*set_cr0)(struct kvm_vcpu *vcpu, unsigned long cr0); - int (*set_cr4)(struct kvm_vcpu *vcpu, unsigned long cr4); + bool (*is_valid_cr4)(struct kvm_vcpu *vcpu, unsigned long cr0); + void (*set_cr4)(struct kvm_vcpu *vcpu, unsigned long cr4); int (*set_efer)(struct kvm_vcpu *vcpu, u64 efer); void (*get_idt)(struct kvm_vcpu *vcpu, struct desc_ptr *dt); void (*set_idt)(struct kvm_vcpu *vcpu, struct desc_ptr *dt); diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c index 9bc166a5d453..442705517caf 100644 --- a/arch/x86/kvm/svm/svm.c +++ b/arch/x86/kvm/svm/svm.c @@ -1692,7 +1692,12 @@ void svm_set_cr0(struct kvm_vcpu *vcpu, unsigned long cr0) update_cr0_intercept(svm); }
-int svm_set_cr4(struct kvm_vcpu *vcpu, unsigned long cr4) +static bool svm_is_valid_cr4(struct kvm_vcpu *vcpu, unsigned long cr4) +{ + return true; +} + +void svm_set_cr4(struct kvm_vcpu *vcpu, unsigned long cr4) { unsigned long host_cr4_mce = cr4_read_shadow() & X86_CR4_MCE; unsigned long old_cr4 = to_svm(vcpu)->vmcb->save.cr4; @@ -1706,7 +1711,6 @@ int svm_set_cr4(struct kvm_vcpu *vcpu, unsigned long cr4) cr4 |= host_cr4_mce; to_svm(vcpu)->vmcb->save.cr4 = cr4; vmcb_mark_dirty(to_svm(vcpu)->vmcb, VMCB_CR); - return 0; }
static void svm_set_segment(struct kvm_vcpu *vcpu, @@ -4238,6 +4242,7 @@ static struct kvm_x86_ops svm_x86_ops __initdata = { .get_cpl = svm_get_cpl, .get_cs_db_l_bits = kvm_get_cs_db_l_bits, .set_cr0 = svm_set_cr0, + .is_valid_cr4 = svm_is_valid_cr4, .set_cr4 = svm_set_cr4, .set_efer = svm_set_efer, .get_idt = svm_get_idt, diff --git a/arch/x86/kvm/svm/svm.h b/arch/x86/kvm/svm/svm.h index 2c007241fbf5..10aba1dd264e 100644 --- a/arch/x86/kvm/svm/svm.h +++ b/arch/x86/kvm/svm/svm.h @@ -355,7 +355,7 @@ void svm_vcpu_free_msrpm(u32 *msrpm);
int svm_set_efer(struct kvm_vcpu *vcpu, u64 efer); void svm_set_cr0(struct kvm_vcpu *vcpu, unsigned long cr0); -int svm_set_cr4(struct kvm_vcpu *vcpu, unsigned long cr4); +void svm_set_cr4(struct kvm_vcpu *vcpu, unsigned long cr4); void svm_flush_tlb(struct kvm_vcpu *vcpu); void disable_nmi_singlestep(struct vcpu_svm *svm); bool svm_smi_blocked(struct kvm_vcpu *vcpu); diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c index c4e37d81b158..3228db4db5df 100644 --- a/arch/x86/kvm/vmx/nested.c +++ b/arch/x86/kvm/vmx/nested.c @@ -4879,7 +4879,7 @@ static int handle_vmon(struct kvm_vcpu *vcpu) /* * The Intel VMX Instruction Reference lists a bunch of bits that are * prerequisite to running VMXON, most notably cr4.VMXE must be set to - * 1 (see vmx_set_cr4() for when we allow the guest to set this). + * 1 (see vmx_is_valid_cr4() for when we allow the guest to set this). * Otherwise, we should fail with #UD. But most faulting conditions * have already been checked by hardware, prior to the VM-exit for * VMXON. We do test guest cr4.VMXE because processor CR4 always has diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c index 154ec5d8cdf5..b33d0f283d4f 100644 --- a/arch/x86/kvm/vmx/vmx.c +++ b/arch/x86/kvm/vmx/vmx.c @@ -3183,7 +3183,23 @@ static void vmx_load_mmu_pgd(struct kvm_vcpu *vcpu, unsigned long pgd, vmcs_writel(GUEST_CR3, guest_cr3); }
-int vmx_set_cr4(struct kvm_vcpu *vcpu, unsigned long cr4) +static bool vmx_is_valid_cr4(struct kvm_vcpu *vcpu, unsigned long cr4) +{ + /* + * We operate under the default treatment of SMM, so VMX cannot be + * enabled under SMM. Note, whether or not VMXE is allowed at all is + * handled by kvm_valid_cr4(). + */ + if ((cr4 & X86_CR4_VMXE) && is_smm(vcpu)) + return false; + + if (to_vmx(vcpu)->nested.vmxon && !nested_cr4_valid(vcpu, cr4)) + return false; + + return true; +} + +void vmx_set_cr4(struct kvm_vcpu *vcpu, unsigned long cr4) { struct vcpu_vmx *vmx = to_vmx(vcpu); /* @@ -3211,17 +3227,6 @@ int vmx_set_cr4(struct kvm_vcpu *vcpu, unsigned long cr4) } }
- /* - * We operate under the default treatment of SMM, so VMX cannot be - * enabled under SMM. Note, whether or not VMXE is allowed at all is - * handled by kvm_valid_cr4(). - */ - if ((cr4 & X86_CR4_VMXE) && is_smm(vcpu)) - return 1; - - if (vmx->nested.vmxon && !nested_cr4_valid(vcpu, cr4)) - return 1; - vcpu->arch.cr4 = cr4; kvm_register_mark_available(vcpu, VCPU_EXREG_CR4);
@@ -3252,7 +3257,6 @@ int vmx_set_cr4(struct kvm_vcpu *vcpu, unsigned long cr4)
vmcs_writel(CR4_READ_SHADOW, cr4); vmcs_writel(GUEST_CR4, hw_cr4); - return 0; }
void vmx_get_segment(struct kvm_vcpu *vcpu, struct kvm_segment *var, int seg) @@ -7748,6 +7752,7 @@ static struct kvm_x86_ops vmx_x86_ops __initdata = { .get_cpl = vmx_get_cpl, .get_cs_db_l_bits = vmx_get_cs_db_l_bits, .set_cr0 = vmx_set_cr0, + .is_valid_cr4 = vmx_is_valid_cr4, .set_cr4 = vmx_set_cr4, .set_efer = vmx_set_efer, .get_idt = vmx_get_idt, diff --git a/arch/x86/kvm/vmx/vmx.h b/arch/x86/kvm/vmx/vmx.h index a6b52d3a39c9..24903f05c204 100644 --- a/arch/x86/kvm/vmx/vmx.h +++ b/arch/x86/kvm/vmx/vmx.h @@ -347,7 +347,7 @@ u32 vmx_get_interrupt_shadow(struct kvm_vcpu *vcpu); void vmx_set_interrupt_shadow(struct kvm_vcpu *vcpu, int mask); int vmx_set_efer(struct kvm_vcpu *vcpu, u64 efer); void vmx_set_cr0(struct kvm_vcpu *vcpu, unsigned long cr0); -int vmx_set_cr4(struct kvm_vcpu *vcpu, unsigned long cr4); +void vmx_set_cr4(struct kvm_vcpu *vcpu, unsigned long cr4); void set_cr4_guest_host_mask(struct vcpu_vmx *vmx); void ept_save_pdptrs(struct kvm_vcpu *vcpu); void vmx_get_segment(struct kvm_vcpu *vcpu, struct kvm_segment *var, int seg); diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 98422a53bb1e..5f4f855bb3b1 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -986,6 +986,9 @@ int kvm_valid_cr4(struct kvm_vcpu *vcpu, unsigned long cr4) if (cr4 & vcpu->arch.cr4_guest_rsvd_bits) return -EINVAL;
+ if (!kvm_x86_ops.is_valid_cr4(vcpu, cr4)) + return -EINVAL; + return 0; } EXPORT_SYMBOL_GPL(kvm_valid_cr4); @@ -1020,8 +1023,7 @@ int kvm_set_cr4(struct kvm_vcpu *vcpu, unsigned long cr4) return 1; }
- if (kvm_x86_ops.set_cr4(vcpu, cr4)) - return 1; + kvm_x86_ops.set_cr4(vcpu, cr4);
if (((cr4 ^ old_cr4) & mmu_role_bits) || (!(cr4 & X86_CR4_PCIDE) && (old_cr4 & X86_CR4_PCIDE)))