[PATCH v3 1/2] KVM: VMX: Print VM-instruction error when it may be helpful

[PATCH v3 1/2] KVM: VMX: Print VM-instruction error when it may be helpful

[Jim Mattson]

From: David Matlack <dmatlack@google.com>

Include the value of the "VM-instruction error" field from the current
VMCS (if any) in the error message for VMCLEAR and VMPTRLD, since each
of these instructions may result in more than one VM-instruction
error. Previously, this field was only reported for VMWRITE errors.

Signed-off-by: David Matlack <dmatlack@google.com>
[Rebased and refactored code; dropped the error number for INVVPID and
INVEPT; reworded commit message.]
Signed-off-by: Jim Mattson <jmattson@google.com>
---
 v1 -> v2: Dropped changes to invvpid_error and invept_error.
 v2 -> v3: Changed printf format character from 'd' to 'u'

 arch/x86/kvm/vmx/vmx.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index 610355b9ccce..3a76730584cd 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -392,12 +392,14 @@ noinline void vmwrite_error(unsigned long field, unsigned long value)
 
 noinline void vmclear_error(struct vmcs *vmcs, u64 phys_addr)
 {
-	vmx_insn_failed("kvm: vmclear failed: %p/%llx\n", vmcs, phys_addr);
+	vmx_insn_failed("kvm: vmclear failed: %p/%llx err=%u\n",
+			vmcs, phys_addr, vmcs_read32(VM_INSTRUCTION_ERROR));
 }
 
 noinline void vmptrld_error(struct vmcs *vmcs, u64 phys_addr)
 {
-	vmx_insn_failed("kvm: vmptrld failed: %p/%llx\n", vmcs, phys_addr);
+	vmx_insn_failed("kvm: vmptrld failed: %p/%llx err=%u\n",
+			vmcs, phys_addr, vmcs_read32(VM_INSTRUCTION_ERROR));
 }
 
 noinline void invvpid_error(unsigned long ext, u16 vpid, gva_t gva)
-- 
2.36.0.512.ge40c2bad7a-goog

[PATCH v3 2/2] KVM: VMX: Print VM-instruction error as unsigned

[Jim Mattson]

Change the printf format character from 'd' to 'u' for the
VM-instruction error in vmwrite_error().

Fixes: 6aa8b732ca01 ("[PATCH] kvm: userspace interface")
Reported-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Jim Mattson <jmattson@google.com>
---
 arch/x86/kvm/vmx/vmx.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index 3a76730584cd..f558a14851f1 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -386,7 +386,7 @@ asmlinkage void vmread_error(unsigned long field, bool fault)
 
 noinline void vmwrite_error(unsigned long field, unsigned long value)
 {
-	vmx_insn_failed("kvm: vmwrite failed: field=%lx val=%lx err=%d\n",
+	vmx_insn_failed("kvm: vmwrite failed: field=%lx val=%lx err=%u\n",
 			field, value, vmcs_read32(VM_INSTRUCTION_ERROR));
 }
 
-- 
2.36.0.512.ge40c2bad7a-goog

Re: [PATCH v3 2/2] KVM: VMX: Print VM-instruction error as unsigned

[Sean Christopherson]

On Tue, May 10, 2022, Jim Mattson wrote:
> Change the printf format character from 'd' to 'u' for the
> VM-instruction error in vmwrite_error().
> 
> Fixes: 6aa8b732ca01 ("[PATCH] kvm: userspace interface")
> Reported-by: Sean Christopherson <seanjc@google.com>
> Signed-off-by: Jim Mattson <jmattson@google.com>
> ---

Reviewed-by: Sean Christopherson <seanjc@google.com>

Re: [PATCH v3 2/2] KVM: VMX: Print VM-instruction error as unsigned

[Jim Mattson]

On Tue, May 10, 2022 at 4:51 PM Sean Christopherson <seanjc@google.com> wrote:
>
> On Tue, May 10, 2022, Jim Mattson wrote:
> > Change the printf format character from 'd' to 'u' for the
> > VM-instruction error in vmwrite_error().
> >
> > Fixes: 6aa8b732ca01 ("[PATCH] kvm: userspace interface")
> > Reported-by: Sean Christopherson <seanjc@google.com>
> > Signed-off-by: Jim Mattson <jmattson@google.com>
> > ---
>
> Reviewed-by: Sean Christopherson <seanjc@google.com>

Paolo?

Re: [PATCH v3 1/2] KVM: VMX: Print VM-instruction error when it may be helpful

[Sean Christopherson]

On Tue, May 10, 2022, Jim Mattson wrote:
> From: David Matlack <dmatlack@google.com>
> 
> Include the value of the "VM-instruction error" field from the current
> VMCS (if any) in the error message for VMCLEAR and VMPTRLD, since each
> of these instructions may result in more than one VM-instruction
> error. Previously, this field was only reported for VMWRITE errors.
> 
> Signed-off-by: David Matlack <dmatlack@google.com>
> [Rebased and refactored code; dropped the error number for INVVPID and
> INVEPT; reworded commit message.]
> Signed-off-by: Jim Mattson <jmattson@google.com>
> ---

I do think it'd be worthwhile to add the safe VMREAD variant, but I don't care
enough to hold this up.

Reviewed-by: Sean Christopherson <seanjc@google.com>