Re: [PATCH v2 2/2] target/arm: Catch invalid kvm state also for hvf

[Peter Maydell <peter.maydell@linaro.org>]

On Tue, 21 Jun 2022 at 12:41, Peter Maydell <peter.maydell@linaro.org> wrote:
>
> On Mon, 20 Jun 2022 at 20:22, Alexander Graf <agraf@csgraf.de> wrote:
> >
> > Some features such as running in EL3 or running M profile code are
> > incompatible with virtualization as QEMU implements it today. To prevent
> > users from picking invalid configurations on other virt solutions like
> > Hvf, let's run the same checks there too.
> >
> > Resolves: https://gitlab.com/qemu-project/qemu/-/issues/1073
> > Signed-off-by: Alexander Graf <agraf@csgraf.de>
>
>
> > --- a/target/arm/cpu.c
> > +++ b/target/arm/cpu.c
> > @@ -1490,7 +1490,7 @@ static void arm_cpu_realizefn(DeviceState *dev, Error **errp)
> >          }
> >      }
> >
> > -    if (kvm_enabled()) {
> > +    if (!tcg_enabled()) {
>
> I'm a bit surprised we don't need to also have "&& !qtest_enabled()",
> but I guess if "make check" works then we're fine :-)

In fact you do need to handle qtest here too, otherwise
lots of tests in 'make check' barf on the unexpected error...

I'm going to squash the following fix in and take the patchset into
target-arm.next. (PS: you forgot the cover letter, I think ?)

diff --git a/target/arm/cpu.c b/target/arm/cpu.c
index 0862dcd63cb..d9c4a9f56d2 100644
--- a/target/arm/cpu.c
+++ b/target/arm/cpu.c
@@ -39,6 +39,7 @@
 #include "hw/boards.h"
 #endif
 #include "sysemu/tcg.h"
+#include "sysemu/qtest.h"
 #include "sysemu/hw_accel.h"
 #include "kvm_arm.h"
 #include "disas/capstone.h"
@@ -1490,8 +1491,12 @@ static void arm_cpu_realizefn(DeviceState *dev,
Error **errp)
         }
     }

-    if (!tcg_enabled()) {
+    if (!tcg_enabled() && !qtest_enabled()) {
         /*
+         * We assume that no accelerator except TCG (and the "not really an
+         * accelerator" qtest) can handle these features, because Arm hardware
+         * virtualization can't virtualize them.
+         *
          * Catch all the cases which might cause us to create more than one
          * address space for the CPU (otherwise we will assert() later in
          * cpu_address_space_init()).


thanks
-- PMM