Messages in this thread Patch in this message | | | From | Yu-cheng Yu <> | Subject | [PATCH 1/3] x86/fpu/xstate: Fix last_good_offset in setup_xstate_features() | Date | Thu, 9 Jan 2020 13:14:50 -0800 |
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The function setup_xstate_features() uses CPUID to find each xfeature's standard-format offset and size. Since XSAVES always uses the compacted format, supervisor xstates are *NEVER* in the standard-format and their offsets are left as -1's. However, they are still being tracked as last_good_offset.
Fix it by tracking only user xstate offsets.
Signed-off-by: Yu-cheng Yu <yu-cheng.yu@intel.com> Reviewed-by: Dave Hansen <dave.hansen@linux.intel.com> --- arch/x86/kernel/fpu/xstate.c | 24 ++++++++++++++---------- 1 file changed, 14 insertions(+), 10 deletions(-)
diff --git a/arch/x86/kernel/fpu/xstate.c b/arch/x86/kernel/fpu/xstate.c index a1806598aaa4..3ef3603bcfc5 100644 --- a/arch/x86/kernel/fpu/xstate.c +++ b/arch/x86/kernel/fpu/xstate.c @@ -265,22 +265,26 @@ static void __init setup_xstate_features(void) cpuid_count(XSTATE_CPUID, i, &eax, &ebx, &ecx, &edx); + xstate_sizes[i] = eax; + /* * If an xfeature is supervisor state, the offset * in EBX is invalid. We leave it to -1. */ - if (xfeature_is_user(i)) + if (xfeature_is_user(i)) { xstate_offsets[i] = ebx; - xstate_sizes[i] = eax; - /* - * In our xstate size checks, we assume that the - * highest-numbered xstate feature has the - * highest offset in the buffer. Ensure it does. - */ - WARN_ONCE(last_good_offset > xstate_offsets[i], - "x86/fpu: misordered xstate at %d\n", last_good_offset); - last_good_offset = xstate_offsets[i]; + /* + * In our xstate size checks, we assume that the + * highest-numbered xstate feature has the + * highest offset in the buffer. Ensure it does. + */ + WARN_ONCE(last_good_offset > xstate_offsets[i], + "x86/fpu: misordered xstate at %d\n", + last_good_offset); + + last_good_offset = xstate_offsets[i]; + } } } -- 2.21.0
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