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| author | Kirill A. Shutemov <kirill.shutemov@linux.intel.com> | 2023-03-12 14:26:06 +0300 |
|---|---|---|
| committer | Dave Hansen <dave.hansen@linux.intel.com> | 2023-03-16 13:08:40 -0700 |
| commit | 23e5d9ec2bab53c4e5fbac675304e699726c1ac5 (patch) | |
| tree | 4a147d3d5733a4b57a1e4d4e99f99e62553fdc17 /arch/x86/kernel/process_64.c | |
| parent | 400b9b93441cd4e2fe824a70140f3d5a2a9c802b (diff) | |
| download | lwn-23e5d9ec2bab53c4e5fbac675304e699726c1ac5.tar.gz lwn-23e5d9ec2bab53c4e5fbac675304e699726c1ac5.zip | |
x86/mm/iommu/sva: Make LAM and SVA mutually exclusive
IOMMU and SVA-capable devices know nothing about LAM and only expect
canonical addresses. An attempt to pass down tagged pointer will lead
to address translation failure.
By default do not allow to enable both LAM and use SVA in the same
process.
The new ARCH_FORCE_TAGGED_SVA arch_prctl() overrides the limitation.
By using the arch_prctl() userspace takes responsibility to never pass
tagged address to the device.
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: Ashok Raj <ashok.raj@intel.com>
Reviewed-by: Jacob Pan <jacob.jun.pan@linux.intel.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/all/20230312112612.31869-12-kirill.shutemov%40linux.intel.com
Diffstat (limited to 'arch/x86/kernel/process_64.c')
| -rw-r--r-- | arch/x86/kernel/process_64.c | 7 |
1 files changed, 7 insertions, 0 deletions
diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c index 186f34add865..b46924c9e46d 100644 --- a/arch/x86/kernel/process_64.c +++ b/arch/x86/kernel/process_64.c @@ -756,6 +756,10 @@ static int prctl_enable_tagged_addr(struct mm_struct *mm, unsigned long nr_bits) if (current->mm != mm) return -EINVAL; + if (mm_valid_pasid(mm) && + !test_bit(MM_CONTEXT_FORCE_TAGGED_SVA, &mm->context.flags)) + return -EINTR; + if (mmap_write_lock_killable(mm)) return -EINTR; @@ -878,6 +882,9 @@ long do_arch_prctl_64(struct task_struct *task, int option, unsigned long arg2) (unsigned long __user *)arg2); case ARCH_ENABLE_TAGGED_ADDR: return prctl_enable_tagged_addr(task->mm, arg2); + case ARCH_FORCE_TAGGED_SVA: + set_bit(MM_CONTEXT_FORCE_TAGGED_SVA, &task->mm->context.flags); + return 0; case ARCH_GET_MAX_TAG_BITS: if (!cpu_feature_enabled(X86_FEATURE_LAM)) return put_user(0, (unsigned long __user *)arg2); |