[v3,1/2] target/arm: kvm: Inject events at the last stage of sync

Message ID 20200312003401.29017-2-beata.michalska@linaro.org
State New
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Series
  • target/arm: kvm: Support for KVM DABT with no valid ISS
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Commit Message

Beata Michalska March 12, 2020, 12:34 a.m.
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 | 15 ++++++++++-----
 target/arm/kvm64.c | 15 ++++++++++-----
 2 files changed, 20 insertions(+), 10 deletions(-)

-- 
2.7.4

Comments

Andrew Jones March 12, 2020, 9:52 a.m. | #1
On Thu, Mar 12, 2020 at 12:34:00AM +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 | 15 ++++++++++-----

>  target/arm/kvm64.c | 15 ++++++++++-----

>  2 files changed, 20 insertions(+), 10 deletions(-)

>


Reviewed-by: Andrew Jones <drjones@redhat.com>
Peter Maydell March 12, 2020, 4:32 p.m. | #2
On Thu, 12 Mar 2020 at 00:34, Beata Michalska
<beata.michalska@linaro.org> 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>


Hi; I'm going to take patch 1 into target-arm.next since it
seems worth having on its own and I'm doing a pullreq today
anyway. Andrew's given you feedback on patch 2.

thanks
-- PMM
Beata Michalska March 15, 2020, 6:35 p.m. | #3
On Thu, 12 Mar 2020 at 16:33, Peter Maydell <peter.maydell@linaro.org> wrote:
>

> On Thu, 12 Mar 2020 at 00:34, Beata Michalska

> <beata.michalska@linaro.org> 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>

>

> Hi; I'm going to take patch 1 into target-arm.next since it

> seems worth having on its own and I'm doing a pullreq today

> anyway. Andrew's given you feedback on patch 2.

>

Hi,

Thanks for that. Will drop this one from the next version of the patchset
once I address all the comments.

BR
Beata
> thanks

> -- PMM

Patch

diff --git a/target/arm/kvm32.c b/target/arm/kvm32.c
index f703c4f..f271181 100644
--- a/target/arm/kvm32.c
+++ b/target/arm/kvm32.c
@@ -409,17 +409,22 @@  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;
     }
 
+    /*
+     * Setting VCPU events should be triggered after syncing the registers
+     * to avoid overwriting potential changes made by KVM upon calling
+     * KVM_SET_VCPU_EVENTS ioctl
+     */
+    ret = kvm_put_vcpu_events(cpu);
+    if (ret) {
+        return ret;
+    }
+
     kvm_arm_sync_mpstate_to_kvm(cpu);
 
     return ret;
diff --git a/target/arm/kvm64.c b/target/arm/kvm64.c
index 93ba144..be5b31c 100644
--- a/target/arm/kvm64.c
+++ b/target/arm/kvm64.c
@@ -1094,17 +1094,22 @@  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;
     }
 
+   /*
+    * Setting VCPU events should be triggered after syncing the registers
+    * to avoid overwriting potential changes made by KVM upon calling
+    * KVM_SET_VCPU_EVENTS ioctl
+    */
+    ret = kvm_put_vcpu_events(cpu);
+    if (ret) {
+        return ret;
+    }
+
     kvm_arm_sync_mpstate_to_kvm(cpu);
 
     return ret;