Messages in this thread | | | Date | Wed, 28 Sep 2022 15:16:42 -0700 | Subject | Re: [PATCH v2 4/4] x86/fpu: Correct the legacy state offset and size information | From | "Chang S. Bae" <> |
| |
On 9/28/2022 2:06 PM, Sean Christopherson wrote: > On Thu, Sep 22, 2022, Chang S. Bae wrote: >> >> diff --git a/arch/x86/kernel/fpu/xstate.c b/arch/x86/kernel/fpu/xstate.c >> index a3f7045d1f8e..ac2ec5d6e7e4 100644 >> --- a/arch/x86/kernel/fpu/xstate.c >> +++ b/arch/x86/kernel/fpu/xstate.c >> @@ -143,8 +143,13 @@ static unsigned int xfeature_get_offset(u64 xcomp_bv, int xfeature) >> * offsets. >> */ >> if (!cpu_feature_enabled(X86_FEATURE_XCOMPACTED) || >> - xfeature <= XFEATURE_SSE) >> + xfeature <= XFEATURE_SSE) { >> + if (xfeature <= XFEATURE_SSE) >> + pr_warn("The legacy state (%d) is discontiguously located.\n", >> + xfeature); > > pr_warn() here isn't warranted. copy_uabi_to_xstate() calls this with non-extended > features,
I think patch1 makes changes not to call this for legacy features anymore.
> which is perfectly fine since it manually handles MXCSR. And that helper > is directly reachable by userspace, i.e. userspace can spam the pr_warn().
I don't think I get your point. I assume that helper is __raw_xsave_addr(). But then I'm missing how it can be directly reached by userspace.
Thanks, Chang
| |