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authorRik van Riel <riel@redhat.com>2017-09-23 15:00:04 +0200
committerIngo Molnar <mingo@kernel.org>2017-09-24 13:04:34 +0200
commit0852b374173bb57f870d78e6c6839c77b339be5f (patch)
tree5dc1a0236423ee5b4708d534a7cbb7fd898d2bbc /arch/x86/include/asm
parent99dc26bda233ee722bbd370bddf20beece3ffb93 (diff)
x86/fpu: Add FPU state copying quirk to handle XRSTOR failure on Intel Skylake CPUs
On Skylake CPUs I noticed that XRSTOR is unable to deal with states created by copyout_from_xsaves() if the xstate has only SSE/YMM state, and no FP state. That is, xfeatures had XFEATURE_MASK_SSE set, but not XFEATURE_MASK_FP. The reason is that part of the SSE/YMM state lives in the MXCSR and MXCSR_FLAGS fields of the FP state. Ensure that whenever we copy SSE or YMM state around, the MXCSR and MXCSR_FLAGS fields are also copied around. Signed-off-by: Rik van Riel <riel@redhat.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Andy Lutomirski <luto@kernel.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Borislav Petkov <bp@suse.de> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Eric Biggers <ebiggers3@gmail.com> Cc: Fenghua Yu <fenghua.yu@intel.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Yu-cheng Yu <yu-cheng.yu@intel.com> Link: http://lkml.kernel.org/r/20170210085445.0f1cc708@annuminas.surriel.com Link: http://lkml.kernel.org/r/20170923130016.21448-22-mingo@kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'arch/x86/include/asm')
-rw-r--r--arch/x86/include/asm/fpu/types.h3
1 files changed, 3 insertions, 0 deletions
diff --git a/arch/x86/include/asm/fpu/types.h b/arch/x86/include/asm/fpu/types.h
index 0c314a397cf5..71db45ca8870 100644
--- a/arch/x86/include/asm/fpu/types.h
+++ b/arch/x86/include/asm/fpu/types.h
@@ -68,6 +68,9 @@ struct fxregs_state {
/* Default value for fxregs_state.mxcsr: */
#define MXCSR_DEFAULT 0x1f80
+/* Copy both mxcsr & mxcsr_flags with a single u64 memcpy: */
+#define MXCSR_AND_FLAGS_SIZE sizeof(u64)
+
/*
* Software based FPU emulation state. This is arbitrary really,
* it matches the x87 format to make it easier to understand:

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