diff mbox series

[v6,3/4] KVM: x86: allow kvm_x86_ops.set_efer to return an error value

Message ID 20200922211025.175547-4-mlevitsk@redhat.com (mailing list archive)
State New, archived
Headers show
Series KVM: nSVM: ondemand nested state allocation | expand

Commit Message

Maxim Levitsky Sept. 22, 2020, 9:10 p.m. UTC 
This will be used to signal an error to the userspace, in case
the vendor code failed during handling of this msr. (e.g -ENOMEM)

Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com>
---
 arch/x86/include/asm/kvm_host.h | 2 +-
 arch/x86/kvm/svm/svm.c          | 3 ++-
 arch/x86/kvm/svm/svm.h          | 2 +-
 arch/x86/kvm/vmx/vmx.c          | 6 ++++--
 arch/x86/kvm/x86.c              | 8 +++++++-
 5 files changed, 15 insertions(+), 6 deletions(-)

Comments

Sean Christopherson Sept. 29, 2020, 5:12 a.m. UTC | #1 
On Wed, Sep 23, 2020 at 12:10:24AM +0300, Maxim Levitsky wrote:
> This will be used to signal an error to the userspace, in case
> the vendor code failed during handling of this msr. (e.g -ENOMEM)
> 
> Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com>
> ---
> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
> index e4b07be450d4e..df53baa0059fe 100644
> --- a/arch/x86/kvm/x86.c
> +++ b/arch/x86/kvm/x86.c
> @@ -1456,6 +1456,7 @@ static int set_efer(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
>  {
>  	u64 old_efer = vcpu->arch.efer;
>  	u64 efer = msr_info->data;
> +	int r;
>  
>  	if (efer & efer_reserved_bits)
>  		return 1;
> @@ -1472,7 +1473,12 @@ static int set_efer(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
>  	efer &= ~EFER_LMA;
>  	efer |= vcpu->arch.efer & EFER_LMA;
>  
> -	kvm_x86_ops.set_efer(vcpu, efer);
> +	r = kvm_x86_ops.set_efer(vcpu, efer);
> +

Nit: IMO, omitting the newline would help the reader make a direct connection
between setting 'r' and checking 'r'.

> +	if (r) {
> +		WARN_ON(r > 0);
> +		return r;
> +	}
>  
>  	/* Update reserved bits */
>  	if ((efer ^ old_efer) & EFER_NX)
> -- 
> 2.26.2
>
diff mbox series

Patch

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 5303dbc5c9bce..b273c199b9a55 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -1069,7 +1069,7 @@  struct kvm_x86_ops {
 	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);
-	void (*set_efer)(struct kvm_vcpu *vcpu, u64 efer);
+	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);
 	void (*get_gdt)(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 3da5b2f1b4a19..18f8af55e970a 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -263,7 +263,7 @@  static int get_max_npt_level(void)
 #endif
 }
 
-void svm_set_efer(struct kvm_vcpu *vcpu, u64 efer)
+int svm_set_efer(struct kvm_vcpu *vcpu, u64 efer)
 {
 	struct vcpu_svm *svm = to_svm(vcpu);
 	vcpu->arch.efer = efer;
@@ -283,6 +283,7 @@  void svm_set_efer(struct kvm_vcpu *vcpu, u64 efer)
 
 	svm->vmcb->save.efer = efer | EFER_SVME;
 	vmcb_mark_dirty(svm->vmcb, VMCB_CR);
+	return 0;
 }
 
 static int is_external_interrupt(u32 info)
diff --git a/arch/x86/kvm/svm/svm.h b/arch/x86/kvm/svm/svm.h
index 45496775f0db2..1e1842de0efe7 100644
--- a/arch/x86/kvm/svm/svm.h
+++ b/arch/x86/kvm/svm/svm.h
@@ -338,7 +338,7 @@  static inline bool gif_set(struct vcpu_svm *svm)
 #define MSR_INVALID				0xffffffffU
 
 u32 svm_msrpm_offset(u32 msr);
-void svm_set_efer(struct kvm_vcpu *vcpu, u64 efer);
+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_flush_tlb(struct kvm_vcpu *vcpu);
diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index 6f9a0c6d5dc59..7f7451ff80ffc 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -2835,13 +2835,14 @@  static void enter_rmode(struct kvm_vcpu *vcpu)
 	kvm_mmu_reset_context(vcpu);
 }
 
-void vmx_set_efer(struct kvm_vcpu *vcpu, u64 efer)
+int vmx_set_efer(struct kvm_vcpu *vcpu, u64 efer)
 {
 	struct vcpu_vmx *vmx = to_vmx(vcpu);
 	struct shared_msr_entry *msr = find_msr_entry(vmx, MSR_EFER);
 
+	/* Nothing to do if hardware doesn't support EFER. */
 	if (!msr)
-		return;
+		return 0;
 
 	vcpu->arch.efer = efer;
 	if (efer & EFER_LMA) {
@@ -2853,6 +2854,7 @@  void vmx_set_efer(struct kvm_vcpu *vcpu, u64 efer)
 		msr->data = efer & ~EFER_LME;
 	}
 	setup_msrs(vmx);
+	return 0;
 }
 
 #ifdef CONFIG_X86_64
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index e4b07be450d4e..df53baa0059fe 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -1456,6 +1456,7 @@  static int set_efer(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
 {
 	u64 old_efer = vcpu->arch.efer;
 	u64 efer = msr_info->data;
+	int r;
 
 	if (efer & efer_reserved_bits)
 		return 1;
@@ -1472,7 +1473,12 @@  static int set_efer(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
 	efer &= ~EFER_LMA;
 	efer |= vcpu->arch.efer & EFER_LMA;
 
-	kvm_x86_ops.set_efer(vcpu, efer);
+	r = kvm_x86_ops.set_efer(vcpu, efer);
+
+	if (r) {
+		WARN_ON(r > 0);
+		return r;
+	}
 
 	/* Update reserved bits */
 	if ((efer ^ old_efer) & EFER_NX)