| Message ID | 20210105190548.13677-1-sstabellini@kernel.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | xen/arm: do not read MVFR2 on arm32 | expand |
On 05/01/2021 19:05, Stefano Stabellini wrote: > MVFR2 is not available on arm32. Don't try to read it. Make MVFR2 arm64 > only. Not really, MVFR2 is allocated when running in AArch32 mode on Armv8. It just doesn't exist on Armv7. See my answer your previous e-mail for more details. > > Fixes: 9cfdb489af81 ("xen/arm: Add ID registers and complete cpuinfo") > Signed-off-by: Stefano Stabellini <stefano.stabellini@xilinx.com> > --- > xen/arch/arm/cpufeature.c | 2 ++ > xen/include/asm-arm/cpufeature.h | 2 +- > 2 files changed, 3 insertions(+), 1 deletion(-) > > diff --git a/xen/arch/arm/cpufeature.c b/xen/arch/arm/cpufeature.c > index 1f6a85aafe..9e3377eae3 100644 > --- a/xen/arch/arm/cpufeature.c > +++ b/xen/arch/arm/cpufeature.c > @@ -150,7 +150,9 @@ void identify_cpu(struct cpuinfo_arm *c) > > c->mvfr.bits[0] = READ_SYSREG(MVFR0_EL1); > c->mvfr.bits[1] = READ_SYSREG(MVFR1_EL1); > +#ifdef CONFIG_ARM_64 > c->mvfr.bits[2] = READ_SYSREG(MVFR2_EL1); > +#endif > } > > /* > diff --git a/xen/include/asm-arm/cpufeature.h b/xen/include/asm-arm/cpufeature.h > index 6058744c18..fa20cb493a 100644 > --- a/xen/include/asm-arm/cpufeature.h > +++ b/xen/include/asm-arm/cpufeature.h > @@ -272,7 +272,7 @@ struct cpuinfo_arm { > } isa32; > > struct { > - register_t bits[3]; > + register_t bits[2 + IS_ENABLED(CONFIG_ARM_64)]; mvfr.bits[2] will be accessed from arch/arm/vcpreg.c, so you will provide garbagge to guest if the user happen to run Xen on Arm32 on Armv8. Given that MVFR2 exists, I think it would be best to keep the definition in cpuinfo_arm around and only hardcode the value in cpufeature.c. Please see my previous e-mail for more rationale on this approach. Cheers,
diff --git a/xen/arch/arm/cpufeature.c b/xen/arch/arm/cpufeature.c index 1f6a85aafe..9e3377eae3 100644 --- a/xen/arch/arm/cpufeature.c +++ b/xen/arch/arm/cpufeature.c @@ -150,7 +150,9 @@ void identify_cpu(struct cpuinfo_arm *c) c->mvfr.bits[0] = READ_SYSREG(MVFR0_EL1); c->mvfr.bits[1] = READ_SYSREG(MVFR1_EL1); +#ifdef CONFIG_ARM_64 c->mvfr.bits[2] = READ_SYSREG(MVFR2_EL1); +#endif } /* diff --git a/xen/include/asm-arm/cpufeature.h b/xen/include/asm-arm/cpufeature.h index 6058744c18..fa20cb493a 100644 --- a/xen/include/asm-arm/cpufeature.h +++ b/xen/include/asm-arm/cpufeature.h @@ -272,7 +272,7 @@ struct cpuinfo_arm { } isa32; struct { - register_t bits[3]; + register_t bits[2 + IS_ENABLED(CONFIG_ARM_64)]; } mvfr; };
MVFR2 is not available on arm32. Don't try to read it. Make MVFR2 arm64 only. Fixes: 9cfdb489af81 ("xen/arm: Add ID registers and complete cpuinfo") Signed-off-by: Stefano Stabellini <stefano.stabellini@xilinx.com> --- xen/arch/arm/cpufeature.c | 2 ++ xen/include/asm-arm/cpufeature.h | 2 +- 2 files changed, 3 insertions(+), 1 deletion(-)