Re: [PATCH v3 4/6] KVM: PPC: mmio: Queue interrupt at kvmppc_emulate_mmio

[Nicholas Piggin]

Excerpts from Fabiano Rosas's message of January 8, 2022 7:00 am:
> If MMIO emulation fails, we queue a Program interrupt to the
> guest. Move that line up into kvmppc_emulate_mmio, which is where we
> set RESUME_GUEST/HOST. This allows the removal of the 'advance'
> variable.
> 
> No functional change, just separation of responsibilities.

Looks cleaner.

Reviewed-by: Nicholas Piggin 

> 
> Signed-off-by: Fabiano Rosas 
> ---
>  arch/powerpc/kvm/emulate_loadstore.c | 8 +---
>  arch/powerpc/kvm/powerpc.c   | 2 +-
>  2 files changed, 2 insertions(+), 8 deletions(-)
> 
> diff --git a/arch/powerpc/kvm/emulate_loadstore.c 
> b/arch/powerpc/kvm/emulate_loadstore.c
> index 48272a9b9c30..4dec920fe4c9 100644
> --- a/arch/powerpc/kvm/emulate_loadstore.c
> +++ b/arch/powerpc/kvm/emulate_loadstore.c
> @@ -73,7 +73,6 @@ int kvmppc_emulate_loadstore(struct kvm_vcpu *vcpu)
>  {
>   u32 inst;
>   enum emulation_result emulated = EMULATE_FAIL;
> - int advance = 1;
>   struct instruction_op op;
>  
>   /* this default type might be overwritten by subcategories */
> @@ -355,15 +354,10 @@ int kvmppc_emulate_loadstore(struct kvm_vcpu *vcpu)
>   }
>   }
>  
> - if (emulated == EMULATE_FAIL) {
> - advance = 0;
> - kvmppc_core_queue_program(vcpu, 0);
> - }
> -
>   trace_kvm_ppc_instr(inst, kvmppc_get_pc(vcpu), emulated);
>  
>   /* Advance past emulated instruction. */
> - if (advance)
> + if (emulated != EMULATE_FAIL)
>   kvmppc_set_pc(vcpu, kvmppc_get_pc(vcpu) + 4);
>  
>   return emulated;
> diff --git a/arch/powerpc/kvm/powerpc.c b/arch/powerpc/kvm/powerpc.c
> index 4d7d0d080232..6daeea4a7de1 100644
> --- a/arch/powerpc/kvm/powerpc.c
> +++ b/arch/powerpc/kvm/powerpc.c
> @@ -307,7 +307,7 @@ int kvmppc_emulate_mmio(struct kvm_vcpu *vcpu)
>   u32 last_inst;
>  
>   kvmppc_get_last_inst(vcpu, INST_GENERIC, _inst);
> - /* XXX Deliver Program interrupt to guest. */
> + kvmppc_core_queue_program(vcpu, 0);
>   pr_info("%s: emulation failed (%08x)\n", __func__, last_inst);
>   r = RESUME_HOST;
>   break;
> -- 
> 2.33.1
> 
> 

Re: [PATCH v3 4/6] KVM: PPC: mmio: Queue interrupt at kvmppc_emulate_mmio

[Alexey Kardashevskiy]

On 08/01/2022 08:00, Fabiano Rosas wrote:

If MMIO emulation fails, we queue a Program interrupt to the
guest. Move that line up into kvmppc_emulate_mmio, which is where we
set RESUME_GUEST/HOST. This allows the removal of the 'advance'
variable.

No functional change, just separation of responsibilities.

Signed-off-by: Fabiano Rosas 



Reviewed-by: Alexey Kardashevskiy 



---
  arch/powerpc/kvm/emulate_loadstore.c | 8 +---
  arch/powerpc/kvm/powerpc.c   | 2 +-
  2 files changed, 2 insertions(+), 8 deletions(-)

diff --git a/arch/powerpc/kvm/emulate_loadstore.c 
b/arch/powerpc/kvm/emulate_loadstore.c
index 48272a9b9c30..4dec920fe4c9 100644
--- a/arch/powerpc/kvm/emulate_loadstore.c
+++ b/arch/powerpc/kvm/emulate_loadstore.c
@@ -73,7 +73,6 @@ int kvmppc_emulate_loadstore(struct kvm_vcpu *vcpu)
  {
u32 inst;
enum emulation_result emulated = EMULATE_FAIL;
-   int advance = 1;
struct instruction_op op;
  
  	/* this default type might be overwritten by subcategories */

@@ -355,15 +354,10 @@ int kvmppc_emulate_loadstore(struct kvm_vcpu *vcpu)
}
}
  
-	if (emulated == EMULATE_FAIL) {

-   advance = 0;
-   kvmppc_core_queue_program(vcpu, 0);
-   }
-
trace_kvm_ppc_instr(inst, kvmppc_get_pc(vcpu), emulated);
  
  	/* Advance past emulated instruction. */

-   if (advance)
+   if (emulated != EMULATE_FAIL)
kvmppc_set_pc(vcpu, kvmppc_get_pc(vcpu) + 4);
  
  	return emulated;

diff --git a/arch/powerpc/kvm/powerpc.c b/arch/powerpc/kvm/powerpc.c
index 4d7d0d080232..6daeea4a7de1 100644
--- a/arch/powerpc/kvm/powerpc.c
+++ b/arch/powerpc/kvm/powerpc.c
@@ -307,7 +307,7 @@ int kvmppc_emulate_mmio(struct kvm_vcpu *vcpu)
u32 last_inst;
  
  		kvmppc_get_last_inst(vcpu, INST_GENERIC, _inst);

-   /* XXX Deliver Program interrupt to guest. */
+   kvmppc_core_queue_program(vcpu, 0);
pr_info("%s: emulation failed (%08x)\n", __func__, last_inst);
r = RESUME_HOST;
break;

[PATCH v3 4/6] KVM: PPC: mmio: Queue interrupt at kvmppc_emulate_mmio

[Fabiano Rosas]

If MMIO emulation fails, we queue a Program interrupt to the
guest. Move that line up into kvmppc_emulate_mmio, which is where we
set RESUME_GUEST/HOST. This allows the removal of the 'advance'
variable.

No functional change, just separation of responsibilities.

Signed-off-by: Fabiano Rosas 
---
 arch/powerpc/kvm/emulate_loadstore.c | 8 +---
 arch/powerpc/kvm/powerpc.c   | 2 +-
 2 files changed, 2 insertions(+), 8 deletions(-)

diff --git a/arch/powerpc/kvm/emulate_loadstore.c 
b/arch/powerpc/kvm/emulate_loadstore.c
index 48272a9b9c30..4dec920fe4c9 100644
--- a/arch/powerpc/kvm/emulate_loadstore.c
+++ b/arch/powerpc/kvm/emulate_loadstore.c
@@ -73,7 +73,6 @@ int kvmppc_emulate_loadstore(struct kvm_vcpu *vcpu)
 {
u32 inst;
enum emulation_result emulated = EMULATE_FAIL;
-   int advance = 1;
struct instruction_op op;
 
/* this default type might be overwritten by subcategories */
@@ -355,15 +354,10 @@ int kvmppc_emulate_loadstore(struct kvm_vcpu *vcpu)
}
}
 
-   if (emulated == EMULATE_FAIL) {
-   advance = 0;
-   kvmppc_core_queue_program(vcpu, 0);
-   }
-
trace_kvm_ppc_instr(inst, kvmppc_get_pc(vcpu), emulated);
 
/* Advance past emulated instruction. */
-   if (advance)
+   if (emulated != EMULATE_FAIL)
kvmppc_set_pc(vcpu, kvmppc_get_pc(vcpu) + 4);
 
return emulated;
diff --git a/arch/powerpc/kvm/powerpc.c b/arch/powerpc/kvm/powerpc.c
index 4d7d0d080232..6daeea4a7de1 100644
--- a/arch/powerpc/kvm/powerpc.c
+++ b/arch/powerpc/kvm/powerpc.c
@@ -307,7 +307,7 @@ int kvmppc_emulate_mmio(struct kvm_vcpu *vcpu)
u32 last_inst;
 
kvmppc_get_last_inst(vcpu, INST_GENERIC, _inst);
-   /* XXX Deliver Program interrupt to guest. */
+   kvmppc_core_queue_program(vcpu, 0);
pr_info("%s: emulation failed (%08x)\n", __func__, last_inst);
r = RESUME_HOST;
break;
-- 
2.33.1