On Wed, Sep 22, 2021 at 11:07:22PM +0200, Peter Zijlstra wrote:
> On Mon, Sep 20, 2021 at 07:23:45PM +0000, Fenghua Yu wrote:
> > diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c
> > index a58800973aed..a25d738ae839 100644
> > --- a/arch/x86/kernel/traps.c
> > +++ b/arch/x86/kernel/traps.c
> > @@ -61,6 +61,7 @@
> > #include <asm/insn.h>
> > #include <asm/insn-eval.h>
> > #include <asm/vdso.h>
> > +#include <asm/iommu.h>
> >
> > #ifdef CONFIG_X86_64
> > #include <asm/x86_init.h>
> > @@ -526,6 +527,14 @@ static enum kernel_gp_hint
> > get_kernel_gp_address(struct pt_regs *regs,
> > return GP_CANONICAL;
> > }
> >
> > +static bool fixup_pasid_exception(void)
> > +{
> > + if (!cpu_feature_enabled(X86_FEATURE_ENQCMD))
> > + return false;
> > +
> > + return __fixup_pasid_exception();
> > +}
That is, shouldn't the above at the very least decode the instruction
causing the #GP and check it's this ENQCMD thing?
> > #define GPFSTR "general protection fault"
> >
> > DEFINE_IDTENTRY_ERRORCODE(exc_general_protection)
> > @@ -538,6 +547,9 @@ DEFINE_IDTENTRY_ERRORCODE(exc_general_protection)
> >
> > cond_local_irq_enable(regs);
> >
> > + if (user_mode(regs) && fixup_pasid_exception())
> > + goto exit;
> > +
> > if (static_cpu_has(X86_FEATURE_UMIP)) {
> > if (user_mode(regs) && fixup_umip_exception(regs))
> > goto exit;
>
> So you're eating any random #GP that might or might not be PASID
> related. And all that witout a comment... Enlighten?
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