diff options
author | Fenghua Yu <fenghua.yu@intel.com> | 2020-09-15 09:30:13 -0700 |
---|---|---|
committer | Borislav Petkov <bp@suse.de> | 2020-09-17 20:22:15 +0200 |
commit | 20f0afd1fb3d7d44f4a3db5a4b6e904410862140 (patch) | |
tree | 0a2b714214912ec3feecdd2193d0df3e51ea7851 /drivers/iommu | |
parent | 1478b99a76534b6c244cfe24fa616280a9441118 (diff) |
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 <luto@kernel.org>
Signed-off-by: Fenghua Yu <fenghua.yu@intel.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Tony Luck <tony.luck@intel.com>
Link: https://lkml.kernel.org/r/1600187413-163670-10-git-send-email-fenghua.yu@intel.com
Diffstat (limited to 'drivers/iommu')
-rw-r--r-- | drivers/iommu/intel/svm.c | 28 |
1 files changed, 27 insertions, 1 deletions
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. |