[PATCH v3] KVM: arm/arm64: fix the incompatible matching for external abort

[PATCH v3] KVM: arm/arm64: fix the incompatible matching for external abort

[Dongjiu Geng]

For this matching, switch expression uses fault type which is
not {I,D}FSC value, but the case expression uses {I,D}FSC,
they are incompatible. So change the switch expression to
use {I,D}FSC.

Signed-off-by: Dongjiu Geng <gengdongjiu@huawei.com>
---
 arch/arm/include/asm/kvm_emulate.h   | 2 +-
 arch/arm64/include/asm/kvm_emulate.h | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/arm/include/asm/kvm_emulate.h b/arch/arm/include/asm/kvm_emulate.h
index 98089ff..7571b4e 100644
--- a/arch/arm/include/asm/kvm_emulate.h
+++ b/arch/arm/include/asm/kvm_emulate.h
@@ -203,7 +203,7 @@ static inline u8 kvm_vcpu_trap_get_fault_type(struct kvm_vcpu *vcpu)
 
 static inline bool kvm_vcpu_dabt_isextabt(struct kvm_vcpu *vcpu)
 {
-	switch (kvm_vcpu_trap_get_fault_type(vcpu)) {
+	switch (kvm_vcpu_trap_get_fault(vcpu)) {
 	case FSC_SEA:
 	case FSC_SEA_TTW0:
 	case FSC_SEA_TTW1:
diff --git a/arch/arm64/include/asm/kvm_emulate.h b/arch/arm64/include/asm/kvm_emulate.h
index e5df3fc..8c918c5 100644
--- a/arch/arm64/include/asm/kvm_emulate.h
+++ b/arch/arm64/include/asm/kvm_emulate.h
@@ -237,7 +237,7 @@ static inline u8 kvm_vcpu_trap_get_fault_type(const struct kvm_vcpu *vcpu)
 
 static inline bool kvm_vcpu_dabt_isextabt(const struct kvm_vcpu *vcpu)
 {
-	switch (kvm_vcpu_trap_get_fault_type(vcpu)) {
+	switch (kvm_vcpu_trap_get_fault(vcpu)) {
 	case FSC_SEA:
 	case FSC_SEA_TTW0:
 	case FSC_SEA_TTW1:
-- 
1.9.1

Re: [PATCH v3] KVM: arm/arm64: fix the incompatible matching for external abort

[Marc Zyngier]

On Sat, Oct 28 2017 at  2:45:59 pm BST, Dongjiu Geng <gengdongjiu@huawei.com> wrote:
> For this matching, switch expression uses fault type which is
> not {I,D}FSC value, but the case expression uses {I,D}FSC,
> they are incompatible. So change the switch expression to
> use {I,D}FSC.

I'm sorry, but I can't manage to parse this commit message. How about
something like this?

"kvm_vcpu_dabt_isextabt() tries to match a full fault syndrome, but
 calls kvm_vcpu_trap_get_fault_type() that only returns the fault class,
 thus reducing the scope of the check. This doesn't cause any observable
 bug yet as we end-up matching a closely related syndrome for which we
 return the same value.

 Using kvm_vcpu_trap_get_fault() instead fixes it for good"

Otherwise:

Acked-by: Marc Zyngier <marc.zyngier@arm.com>

	M.
-- 
Jazz is not dead. It just smells funny.

Re: [PATCH v3] KVM: arm/arm64: fix the incompatible matching for external abort

[gengdongjiu]

On 2017/10/29 9:12, Marc Zyngier wrote:
> I'm sorry, but I can't manage to parse this commit message. How about
> something like this?
> 
> "kvm_vcpu_dabt_isextabt() tries to match a full fault syndrome, but
>  calls kvm_vcpu_trap_get_fault_type() that only returns the fault class,
>  thus reducing the scope of the check. This doesn't cause any observable
>  bug yet as we end-up matching a closely related syndrome for which we
>  return the same value.
> 
>  Using kvm_vcpu_trap_get_fault() instead fixes it for good"

Marc, thank you very much for your pointing out and good suggestion,
will update it. Thanks a lot.