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65ac2e9baa
Note: our xsaves support is currently broken and disabled. This patch does not fix it, but it is an incremental improvement. This might be useful to someone backporting the entire set of XSAVES patches at some point, but it should not be backported alone. Ingo said he wanted something like this (bullets 2 and 3): http://lkml.kernel.org/r/20150808091508.GB32641@gmail.com There are currently two xsave buffer formats: standard and compacted. The standard format is waht 'XSAVE' and 'XSAVEOPT' produce while 'XSAVES' and 'XSAVEC' produce a compacted-formet buffer. (The kernel never uses XSAVEC) But, the XSAVES buffer *ALSO* contains "system state components" which are never saved by a plain XSAVE. So, XSAVES has two things that might make its buffer differently-sized from an XSAVE-produced one. The current code assumes that an XSAVES buffer's size is simply the sum of the sizes of the (user) states which are supported. This seems to work in most cases, but it is not consistent with what the SDM says, and it breaks if we 'align' a component in the buffer. The calculation is also unnecessary work since the CPU *tells* us the size of the buffer directly. This patch just reads the size of the buffer right out of the CPUID leaf instead of trying to derive it. But, blindly trusting the CPU like this is dangerous. We add a verification pass in do_extra_xstate_size_checks() to ensure that the size we calculate matches with what we see from the hardware. When it comes down to it, we trust but verify the CPU. Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: Fenghua Yu <fenghua.yu@intel.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Tim Chen <tim.c.chen@linux.intel.com> Cc: dave@sr71.net Cc: linux-kernel@vger.kernel.org Link: http://lkml.kernel.org/r/20150902233130.234FE1EC@viggo.jf.intel.com Signed-off-by: Ingo Molnar <mingo@kernel.org> |
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| crypto | ||
| entry | ||
| ia32 | ||
| include | ||
| kernel | ||
| kvm | ||
| lguest | ||
| lib | ||
| math-emu | ||
| mm | ||
| net | ||
| oprofile | ||
| pci | ||
| platform | ||
| power | ||
| purgatory | ||
| ras | ||
| realmode | ||
| tools | ||
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| video | ||
| xen | ||
| .gitignore | ||
| Kbuild | ||
| Kconfig | ||
| Kconfig.cpu | ||
| Kconfig.debug | ||
| Makefile | ||
| Makefile_32.cpu | ||
| Makefile.um | ||