diff options
| -rw-r--r-- | arch/x86/include/asm/fpu/api.h | 12 | ||||
| -rw-r--r-- | arch/x86/include/asm/fpu/internal.h | 7 | ||||
| -rw-r--r-- | arch/x86/kernel/fpu/xstate.c | 57 | ||||
| -rw-r--r-- | drivers/iommu/intel/svm.c | 28 |
4 files changed, 103 insertions, 1 deletions
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 */ diff --git a/arch/x86/include/asm/fpu/internal.h b/arch/x86/include/asm/fpu/internal.h index 0a460f2a3f90..341d00eba3f8 100644 --- a/arch/x86/include/asm/fpu/internal.h +++ b/arch/x86/include/asm/fpu/internal.h @@ -583,6 +583,13 @@ static inline void switch_fpu_finish(struct fpu *new_fpu) pkru_val = pk->pkru; } __write_pkru(pkru_val); + + /* + * Expensive PASID MSR write will be avoided in update_pasid() because + * TIF_NEED_FPU_LOAD was set. And the PASID state won't be updated + * unless it's different from mm->pasid to reduce overhead. + */ + update_pasid(); } /* diff --git a/arch/x86/kernel/fpu/xstate.c b/arch/x86/kernel/fpu/xstate.c index 67f1a03b9b23..5d8047441a0a 100644 --- a/arch/x86/kernel/fpu/xstate.c +++ b/arch/x86/kernel/fpu/xstate.c @@ -1402,3 +1402,60 @@ int proc_pid_arch_status(struct seq_file *m, struct pid_namespace *ns, return 0; } #endif /* CONFIG_PROC_PID_ARCH_STATUS */ + +#ifdef CONFIG_IOMMU_SUPPORT +void update_pasid(void) +{ + u64 pasid_state; + u32 pasid; + + if (!cpu_feature_enabled(X86_FEATURE_ENQCMD)) + return; + + if (!current->mm) + return; + + pasid = READ_ONCE(current->mm->pasid); + /* Set the valid bit in the PASID MSR/state only for valid pasid. */ + pasid_state = pasid == PASID_DISABLED ? + pasid : pasid | MSR_IA32_PASID_VALID; + + /* + * No need to hold fregs_lock() since the task's fpstate won't + * be changed by others (e.g. ptrace) while the task is being + * switched to or is in IPI. + */ + if (!test_thread_flag(TIF_NEED_FPU_LOAD)) { + /* The MSR is active and can be directly updated. */ + wrmsrl(MSR_IA32_PASID, pasid_state); + } else { + struct fpu *fpu = ¤t->thread.fpu; + struct ia32_pasid_state *ppasid_state; + struct xregs_state *xsave; + + /* + * The CPU's xstate registers are not currently active. Just + * update the PASID state in the memory buffer here. The + * PASID MSR will be loaded when returning to user mode. + */ + xsave = &fpu->state.xsave; + xsave->header.xfeatures |= XFEATURE_MASK_PASID; + ppasid_state = get_xsave_addr(xsave, XFEATURE_PASID); + /* + * Since XFEATURE_MASK_PASID is set in xfeatures, ppasid_state + * won't be NULL and no need to check its value. + * + * Only update the task's PASID state when it's different + * from the mm's pasid. + */ + if (ppasid_state->pasid != pasid_state) { + /* + * Invalid fpregs so that state restoring will pick up + * the PASID state. + */ + __fpu_invalidate_fpregs_state(fpu); + ppasid_state->pasid = pasid_state; + } + } +} +#endif /* CONFIG_IOMMU_SUPPORT */ diff --git a/drivers/iommu/intel/svm.c b/drivers/iommu/intel/svm.c index fc90a079e228..60ffe083b6d6 100644 --- a/drivers/iommu/intel/svm.c +++ b/drivers/iommu/intel/svm.c @@ -19,6 +19,7 @@ #include <linux/mm_types.h> #include <linux/ioasid.h> #include <asm/page.h> +#include <asm/fpu/api.h> #include "pasid.h" @@ -444,6 +445,24 @@ out: return ret; } +static void _load_pasid(void *unused) +{ + update_pasid(); +} + +static void load_pasid(struct mm_struct *mm, u32 pasid) +{ + mutex_lock(&mm->context.lock); + + /* Synchronize with READ_ONCE in update_pasid(). */ + smp_store_release(&mm->pasid, pasid); + + /* Update PASID MSR on all CPUs running the mm's tasks. */ + on_each_cpu_mask(mm_cpumask(mm), _load_pasid, NULL, true); + + mutex_unlock(&mm->context.lock); +} + /* Caller must hold pasid_mutex, mm reference */ static int intel_svm_bind_mm(struct device *dev, unsigned int flags, @@ -591,6 +610,10 @@ intel_svm_bind_mm(struct device *dev, unsigned int flags, } list_add_tail(&svm->list, &global_svm_list); + if (mm) { + /* The newly allocated pasid is loaded to the mm. */ + load_pasid(mm, svm->pasid); + } } else { /* * Binding a new device with existing PASID, need to setup @@ -654,8 +677,11 @@ static int intel_svm_unbind_mm(struct device *dev, u32 pasid) if (list_empty(&svm->devs)) { ioasid_free(svm->pasid); - if (svm->mm) + if (svm->mm) { mmu_notifier_unregister(&svm->notifier, svm->mm); + /* Clear mm's pasid. */ + load_pasid(svm->mm, PASID_DISABLED); + } list_del(&svm->list); /* We mandate that no page faults may be outstanding * for the PASID when intel_svm_unbind_mm() is called. |