From 20f0afd1fb3d7d44f4a3db5a4b6e904410862140 Mon Sep 17 00:00:00 2001 From: Fenghua Yu Date: Tue, 15 Sep 2020 09:30:13 -0700 Subject: x86/mmu: Allocate/free a PASID A PASID is allocated for an "mm" the first time any thread binds to an SVA-capable device and is freed from the "mm" when the SVA is unbound by the last thread. It's possible for the "mm" to have different PASID values in different binding/unbinding SVA cycles. The mm's PASID (non-zero for valid PASID or 0 for invalid PASID) is propagated to a per-thread PASID MSR for all threads within the mm through IPI, context switch, or inherited. This is done to ensure that a running thread has the right PASID in the MSR matching the mm's PASID. [ bp: s/SVM/SVA/g; massage. ] Suggested-by: Andy Lutomirski Signed-off-by: Fenghua Yu Signed-off-by: Borislav Petkov Reviewed-by: Tony Luck Link: https://lkml.kernel.org/r/1600187413-163670-10-git-send-email-fenghua.yu@intel.com --- arch/x86/include/asm/fpu/api.h | 12 ++++++++++++ 1 file changed, 12 insertions(+) (limited to 'arch/x86/include/asm/fpu/api.h') diff --git a/arch/x86/include/asm/fpu/api.h b/arch/x86/include/asm/fpu/api.h index b774c52e5411..dcd9503b1098 100644 --- a/arch/x86/include/asm/fpu/api.h +++ b/arch/x86/include/asm/fpu/api.h @@ -62,4 +62,16 @@ extern void switch_fpu_return(void); */ extern int cpu_has_xfeatures(u64 xfeatures_mask, const char **feature_name); +/* + * Tasks that are not using SVA have mm->pasid set to zero to note that they + * will not have the valid bit set in MSR_IA32_PASID while they are running. + */ +#define PASID_DISABLED 0 + +#ifdef CONFIG_IOMMU_SUPPORT +/* Update current's PASID MSR/state by mm's PASID. */ +void update_pasid(void); +#else +static inline void update_pasid(void) { } +#endif #endif /* _ASM_X86_FPU_API_H */ -- cgit v1.2.3