diff mbox series

[v2,1/2] target/arm: kvm: Inject events at the last stage of sync

Message ID 20200129202441.12745-2-beata.michalska@linaro.org
State New
Headers show
Series target/arm: kvm: Support for KVM DABT without valid ISS | expand

Commit Message

Beata Michalska Jan. 29, 2020, 8:24 p.m. UTC 
KVM_SET_VCPU_EVENTS might actually lead to vcpu registers being modified.
As such this should be the last step of sync to avoid potential overwriting
of whatever changes KVM might have done.

Signed-off-by: Beata Michalska <beata.michalska@linaro.org>
---
 target/arm/kvm32.c | 20 ++++++++++----------
 target/arm/kvm64.c | 20 ++++++++++----------
 2 files changed, 20 insertions(+), 20 deletions(-)

Comments

Andrew Jones Feb. 4, 2020, 10:34 a.m. UTC | #1 
On Wed, Jan 29, 2020 at 08:24:40PM +0000, Beata Michalska wrote:
> KVM_SET_VCPU_EVENTS might actually lead to vcpu registers being modified.
> As such this should be the last step of sync to avoid potential overwriting
> of whatever changes KVM might have done.
> 
> Signed-off-by: Beata Michalska <beata.michalska@linaro.org>
> ---
>  target/arm/kvm32.c | 20 ++++++++++----------
>  target/arm/kvm64.c | 20 ++++++++++----------
>  2 files changed, 20 insertions(+), 20 deletions(-)
> 
> diff --git a/target/arm/kvm32.c b/target/arm/kvm32.c
> index 32bf8d6..cf2b47f 100644
> --- a/target/arm/kvm32.c
> +++ b/target/arm/kvm32.c
> @@ -386,17 +386,17 @@ int kvm_arch_put_registers(CPUState *cs, int level)
>          return ret;
>      }
>  
> -    ret = kvm_put_vcpu_events(cpu);
> -    if (ret) {
> -        return ret;
> -    }
> -
>      write_cpustate_to_list(cpu, true);
>  
>      if (!write_list_to_kvmstate(cpu, level)) {
>          return EINVAL;
>      }
>  
> +    ret = kvm_put_vcpu_events(cpu);
> +    if (ret) {
> +        return ret;
> +    }
> +

I think we should put a comment above this that says basically the same
thing as the commit message in order to explain why kvm_put_vcpu_events()
*must* be after write_list_to_kvmstate().

>      kvm_arm_sync_mpstate_to_kvm(cpu);
>  
>      return ret;
> @@ -462,11 +462,6 @@ int kvm_arch_get_registers(CPUState *cs)
>      }
>      vfp_set_fpscr(env, fpscr);
>  
> -    ret = kvm_get_vcpu_events(cpu);
> -    if (ret) {
> -        return ret;
> -    }
> -
>      if (!write_kvmstate_to_list(cpu)) {
>          return EINVAL;
>      }
> @@ -475,6 +470,11 @@ int kvm_arch_get_registers(CPUState *cs)
>       */
>      write_list_to_cpustate(cpu);
>  
> +    ret = kvm_get_vcpu_events(cpu);
> +    if (ret) {
> +        return ret;
> +    }
> +

Why are we moving kvm_get_vcpu_events()?

>      kvm_arm_sync_mpstate_to_qemu(cpu);
>  
>      return 0;
> diff --git a/target/arm/kvm64.c b/target/arm/kvm64.c
> index 6344113..d06fd32 100644
> --- a/target/arm/kvm64.c
> +++ b/target/arm/kvm64.c
> @@ -1043,17 +1043,17 @@ int kvm_arch_put_registers(CPUState *cs, int level)
>          return ret;
>      }
>  
> -    ret = kvm_put_vcpu_events(cpu);
> -    if (ret) {
> -        return ret;
> -    }
> -
>      write_cpustate_to_list(cpu, true);
>  
>      if (!write_list_to_kvmstate(cpu, level)) {
>          return -EINVAL;
>      }
>  
> +    ret = kvm_put_vcpu_events(cpu);
> +    if (ret) {
> +        return ret;
> +    }
> +
>      kvm_arm_sync_mpstate_to_kvm(cpu);
>  
>      return ret;
> @@ -1251,11 +1251,6 @@ int kvm_arch_get_registers(CPUState *cs)
>      }
>      vfp_set_fpcr(env, fpr);
>  
> -    ret = kvm_get_vcpu_events(cpu);
> -    if (ret) {
> -        return ret;
> -    }
> -
>      if (!write_kvmstate_to_list(cpu)) {
>          return -EINVAL;
>      }
> @@ -1264,6 +1259,11 @@ int kvm_arch_get_registers(CPUState *cs)
>       */
>      write_list_to_cpustate(cpu);
>  
> +    ret = kvm_get_vcpu_events(cpu);
> +    if (ret) {
> +        return ret;
> +    }
> +
>      kvm_arm_sync_mpstate_to_qemu(cpu);
>  
>      /* TODO: other registers */
> -- 
> 2.7.4
> 
> 

Same comments for kvm64.c as for kvm32.c

Thanks,
drew
Beata Michalska Feb. 6, 2020, 9:41 p.m. UTC | #2 
On Tue, 4 Feb 2020 at 10:34, Andrew Jones <drjones@redhat.com> wrote:
>
> On Wed, Jan 29, 2020 at 08:24:40PM +0000, Beata Michalska wrote:
> > KVM_SET_VCPU_EVENTS might actually lead to vcpu registers being modified.
> > As such this should be the last step of sync to avoid potential overwriting
> > of whatever changes KVM might have done.
> >
> > Signed-off-by: Beata Michalska <beata.michalska@linaro.org>
> > ---
> >  target/arm/kvm32.c | 20 ++++++++++----------
> >  target/arm/kvm64.c | 20 ++++++++++----------
> >  2 files changed, 20 insertions(+), 20 deletions(-)
> >
> > diff --git a/target/arm/kvm32.c b/target/arm/kvm32.c
> > index 32bf8d6..cf2b47f 100644
> > --- a/target/arm/kvm32.c
> > +++ b/target/arm/kvm32.c
> > @@ -386,17 +386,17 @@ int kvm_arch_put_registers(CPUState *cs, int level)
> >          return ret;
> >      }
> >
> > -    ret = kvm_put_vcpu_events(cpu);
> > -    if (ret) {
> > -        return ret;
> > -    }
> > -
> >      write_cpustate_to_list(cpu, true);
> >
> >      if (!write_list_to_kvmstate(cpu, level)) {
> >          return EINVAL;
> >      }
> >
> > +    ret = kvm_put_vcpu_events(cpu);
> > +    if (ret) {
> > +        return ret;
> > +    }
> > +
>
> I think we should put a comment above this that says basically the same
> thing as the commit message in order to explain why kvm_put_vcpu_events()
> *must* be after write_list_to_kvmstate().
>
Will do that.

> >      kvm_arm_sync_mpstate_to_kvm(cpu);
> >
> >      return ret;
> > @@ -462,11 +462,6 @@ int kvm_arch_get_registers(CPUState *cs)
> >      }
> >      vfp_set_fpscr(env, fpscr);
> >
> > -    ret = kvm_get_vcpu_events(cpu);
> > -    if (ret) {
> > -        return ret;
> > -    }
> > -
> >      if (!write_kvmstate_to_list(cpu)) {
> >          return EINVAL;
> >      }
> > @@ -475,6 +470,11 @@ int kvm_arch_get_registers(CPUState *cs)
> >       */
> >      write_list_to_cpustate(cpu);
> >
> > +    ret = kvm_get_vcpu_events(cpu);
> > +    if (ret) {
> > +        return ret;
> > +    }
> > +
>
> Why are we moving kvm_get_vcpu_events()?

This is only to make things consistent with put_registeres.
There is no functional change per se.

BR

Beata

> >      kvm_arm_sync_mpstate_to_qemu(cpu);
> >
> >      return 0;
> > diff --git a/target/arm/kvm64.c b/target/arm/kvm64.c
> > index 6344113..d06fd32 100644
> > --- a/target/arm/kvm64.c
> > +++ b/target/arm/kvm64.c
> > @@ -1043,17 +1043,17 @@ int kvm_arch_put_registers(CPUState *cs, int level)
> >          return ret;
> >      }
> >
> > -    ret = kvm_put_vcpu_events(cpu);
> > -    if (ret) {
> > -        return ret;
> > -    }
> > -
> >      write_cpustate_to_list(cpu, true);
> >
> >      if (!write_list_to_kvmstate(cpu, level)) {
> >          return -EINVAL;
> >      }
> >
> > +    ret = kvm_put_vcpu_events(cpu);
> > +    if (ret) {
> > +        return ret;
> > +    }
> > +
> >      kvm_arm_sync_mpstate_to_kvm(cpu);
> >
> >      return ret;
> > @@ -1251,11 +1251,6 @@ int kvm_arch_get_registers(CPUState *cs)
> >      }
> >      vfp_set_fpcr(env, fpr);
> >
> > -    ret = kvm_get_vcpu_events(cpu);
> > -    if (ret) {
> > -        return ret;
> > -    }
> > -
> >      if (!write_kvmstate_to_list(cpu)) {
> >          return -EINVAL;
> >      }
> > @@ -1264,6 +1259,11 @@ int kvm_arch_get_registers(CPUState *cs)
> >       */
> >      write_list_to_cpustate(cpu);
> >
> > +    ret = kvm_get_vcpu_events(cpu);
> > +    if (ret) {
> > +        return ret;
> > +    }
> > +
> >      kvm_arm_sync_mpstate_to_qemu(cpu);
> >
> >      /* TODO: other registers */
> > --
> > 2.7.4
> >
> >
>
> Same comments for kvm64.c as for kvm32.c
>
> Thanks,
> drew
>
Andrew Jones Feb. 7, 2020, 7:41 a.m. UTC | #3 
On Thu, Feb 06, 2020 at 09:41:10PM +0000, Beata Michalska wrote:
> On Tue, 4 Feb 2020 at 10:34, Andrew Jones <drjones@redhat.com> wrote:
> >
> > On Wed, Jan 29, 2020 at 08:24:40PM +0000, Beata Michalska wrote:
> > > KVM_SET_VCPU_EVENTS might actually lead to vcpu registers being modified.
> > > As such this should be the last step of sync to avoid potential overwriting
> > > of whatever changes KVM might have done.
> > >
> > > Signed-off-by: Beata Michalska <beata.michalska@linaro.org>
> > > ---
> > >  target/arm/kvm32.c | 20 ++++++++++----------
> > >  target/arm/kvm64.c | 20 ++++++++++----------
> > >  2 files changed, 20 insertions(+), 20 deletions(-)
> > >
> > > diff --git a/target/arm/kvm32.c b/target/arm/kvm32.c
> > > index 32bf8d6..cf2b47f 100644
> > > --- a/target/arm/kvm32.c
> > > +++ b/target/arm/kvm32.c
> > > @@ -386,17 +386,17 @@ int kvm_arch_put_registers(CPUState *cs, int level)
> > >          return ret;
> > >      }
> > >
> > > -    ret = kvm_put_vcpu_events(cpu);
> > > -    if (ret) {
> > > -        return ret;
> > > -    }
> > > -
> > >      write_cpustate_to_list(cpu, true);
> > >
> > >      if (!write_list_to_kvmstate(cpu, level)) {
> > >          return EINVAL;
> > >      }
> > >
> > > +    ret = kvm_put_vcpu_events(cpu);
> > > +    if (ret) {
> > > +        return ret;
> > > +    }
> > > +
> >
> > I think we should put a comment above this that says basically the same
> > thing as the commit message in order to explain why kvm_put_vcpu_events()
> > *must* be after write_list_to_kvmstate().
> >
> Will do that.
> 
> > >      kvm_arm_sync_mpstate_to_kvm(cpu);
> > >
> > >      return ret;
> > > @@ -462,11 +462,6 @@ int kvm_arch_get_registers(CPUState *cs)
> > >      }
> > >      vfp_set_fpscr(env, fpscr);
> > >
> > > -    ret = kvm_get_vcpu_events(cpu);
> > > -    if (ret) {
> > > -        return ret;
> > > -    }
> > > -
> > >      if (!write_kvmstate_to_list(cpu)) {
> > >          return EINVAL;
> > >      }
> > > @@ -475,6 +470,11 @@ int kvm_arch_get_registers(CPUState *cs)
> > >       */
> > >      write_list_to_cpustate(cpu);
> > >
> > > +    ret = kvm_get_vcpu_events(cpu);
> > > +    if (ret) {
> > > +        return ret;
> > > +    }
> > > +
> >
> > Why are we moving kvm_get_vcpu_events()?
> 
> This is only to make things consistent with put_registeres.
> There is no functional change per se.

Without a functional change I wouldn't move it. It's much
more appealing to have the final state writes at the bottom
of this function.

Thanks,
drew
diff mbox series

Patch

diff --git a/target/arm/kvm32.c b/target/arm/kvm32.c
index 32bf8d6..cf2b47f 100644
--- a/target/arm/kvm32.c
+++ b/target/arm/kvm32.c
@@ -386,17 +386,17 @@  int kvm_arch_put_registers(CPUState *cs, int level)
         return ret;
     }
 
-    ret = kvm_put_vcpu_events(cpu);
-    if (ret) {
-        return ret;
-    }
-
     write_cpustate_to_list(cpu, true);
 
     if (!write_list_to_kvmstate(cpu, level)) {
         return EINVAL;
     }
 
+    ret = kvm_put_vcpu_events(cpu);
+    if (ret) {
+        return ret;
+    }
+
     kvm_arm_sync_mpstate_to_kvm(cpu);
 
     return ret;
@@ -462,11 +462,6 @@  int kvm_arch_get_registers(CPUState *cs)
     }
     vfp_set_fpscr(env, fpscr);
 
-    ret = kvm_get_vcpu_events(cpu);
-    if (ret) {
-        return ret;
-    }
-
     if (!write_kvmstate_to_list(cpu)) {
         return EINVAL;
     }
@@ -475,6 +470,11 @@  int kvm_arch_get_registers(CPUState *cs)
      */
     write_list_to_cpustate(cpu);
 
+    ret = kvm_get_vcpu_events(cpu);
+    if (ret) {
+        return ret;
+    }
+
     kvm_arm_sync_mpstate_to_qemu(cpu);
 
     return 0;
diff --git a/target/arm/kvm64.c b/target/arm/kvm64.c
index 6344113..d06fd32 100644
--- a/target/arm/kvm64.c
+++ b/target/arm/kvm64.c
@@ -1043,17 +1043,17 @@  int kvm_arch_put_registers(CPUState *cs, int level)
         return ret;
     }
 
-    ret = kvm_put_vcpu_events(cpu);
-    if (ret) {
-        return ret;
-    }
-
     write_cpustate_to_list(cpu, true);
 
     if (!write_list_to_kvmstate(cpu, level)) {
         return -EINVAL;
     }
 
+    ret = kvm_put_vcpu_events(cpu);
+    if (ret) {
+        return ret;
+    }
+
     kvm_arm_sync_mpstate_to_kvm(cpu);
 
     return ret;
@@ -1251,11 +1251,6 @@  int kvm_arch_get_registers(CPUState *cs)
     }
     vfp_set_fpcr(env, fpr);
 
-    ret = kvm_get_vcpu_events(cpu);
-    if (ret) {
-        return ret;
-    }
-
     if (!write_kvmstate_to_list(cpu)) {
         return -EINVAL;
     }
@@ -1264,6 +1259,11 @@  int kvm_arch_get_registers(CPUState *cs)
      */
     write_list_to_cpustate(cpu);
 
+    ret = kvm_get_vcpu_events(cpu);
+    if (ret) {
+        return ret;
+    }
+
     kvm_arm_sync_mpstate_to_qemu(cpu);
 
     /* TODO: other registers */