Re: [PATCH] cpu/cpuid: check CPUID_PAE to determine 36 bit processor address space

[Michael S. Tsirkin]

On Wed, Oct 18, 2023 at 11:08:11PM +0530, Ani Sinha wrote:
> 
> 
> On Wed, 18 Oct, 2023, 5:35 pm Michael S. Tsirkin, <mst@redhat.com> wrote:
> 
>     On Tue, Sep 12, 2023 at 05:36:50PM +0530, Ani Sinha wrote:
>     > PAE mode in x86 supports 36 bit address space. Check the PAE CPUID on 
> the
>     > guest processor and set phys_bits to 36 if PAE feature is set. This is 
> in
>     > addition to checking the presence of PSE36 CPUID feature for setting 36
>     bit
>     > phys_bits.
>     >
>     > Signed-off-by: Ani Sinha <anisinha@redhat.com>
> 
>     Acked-by: Michael S. Tsirkin <mst@redhat.com>
> 
>     who's applying this?
> 
> 
> I thought it would be you? What did I miss?

I just don't play a lot with CPUID flags and might easily miss things.
Used to be Eduardo .. maybe CC him.

> 
> 
>     > ---
>     >  target/i386/cpu.c | 2 +-
>     >  1 file changed, 1 insertion(+), 1 deletion(-)
>     >
>     > Note: Not sure what tests I should be running in order to make sure I am
>     > not breaking any guest OSes. Usual qtests pass.
>     >
>     > diff --git a/target/i386/cpu.c b/target/i386/cpu.c
>     > index 24ee67b42d..f3a5c99117 100644
>     > --- a/target/i386/cpu.c
>     > +++ b/target/i386/cpu.c
>     > @@ -7375,7 +7375,7 @@ static void x86_cpu_realizefn(DeviceState *dev,
>     Error **errp)
>     >              return;
>     >          }
>     > 
>     > -        if (env->features[FEAT_1_EDX] & CPUID_PSE36) {
>     > +        if (env->features[FEAT_1_EDX] & (CPUID_PSE36 | CPUID_PAE)) {
>     >              cpu->phys_bits = 36;
>     >          } else {
>     >              cpu->phys_bits = 32;
>     > --
>     > 2.39.1
> 
>