From: Alexandru Elisei <alexandru.elisei@arm.com> To: catalin.marinas@arm.com, will@kernel.org, oliver.upton@linux.dev, maz@kernel.org, james.morse@arm.com, suzuki.poulose@arm.com, yuzenghui@huawei.com, arnd@arndb.de, akpm@linux-foundation.org, mingo@redhat.com, peterz@infradead.org, juri.lelli@redhat.com, vincent.guittot@linaro.org, dietmar.eggemann@arm.com, rostedt@goodmis.org, bsegall@google.com, mgorman@suse.de, bristot@redhat.com, vschneid@redhat.com, mhiramat@kernel.org, rppt@kernel.org, hughd@google.com Cc: pcc@google.com, steven.price@arm.com, anshuman.khandual@arm.com, vincenzo.frascino@arm.com, david@redhat.com, eugenis@google.com, kcc@google.com, hyesoo.yu@samsung.com, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, kvmarm@lists.linux.dev, linux-fsdevel@vger.kernel.org, linux-arch@vger.kernel.org, linux-mm@kvack.org, linux-trace-kernel@vger.kernel.org Subject: [PATCH RFC v3 16/35] KVM: arm64: Don't deny VM_PFNMAP VMAs when kvm_has_mte() Date: Thu, 25 Jan 2024 16:42:37 +0000 [thread overview] Message-ID: <20240125164256.4147-17-alexandru.elisei@arm.com> (raw) In-Reply-To: <20240125164256.4147-1-alexandru.elisei@arm.com> According to ARM DDI 0487J.a, page D10-5976, a memory location which doesn't have the Normal memory attribute is considered Untagged, and accesses are Tag Unchecked. Tag reads from an Untagged address return 0b0000, and writes are ignored. Linux uses VM_PFNMAP VMAs represent device memory, and Linux doesn't set the VM_MTE_ALLOWED flag for these VMAs. In user_mem_abort(), KVM requires that all VMAs that back guest memory must allow tagging (VM_MTE_ALLOWED flag set), except for VMAs that represent device memory. When a memslot is created or changed, KVM enforces a different behaviour: **all** VMAs that intersect the memslot must allow tagging, even those that represent device memory. This is too restrictive, and can lead to inconsistent behaviour: a VM_PFNMAP VMA that is present when a memslot is created causes KVM_SET_USER_MEMORY_REGION to fail, but if such a VMA is created after the memslot has been created, the virtual machine will run without errors. Change kvm_arch_prepare_memory_region() to allow VM_PFNMAP VMAs when the VM has the MTE capability enabled. Signed-off-by: Alexandru Elisei <alexandru.elisei@arm.com> --- Changes from rfc v2: * New patch. It's a fix, and can be taken independently of the series. arch/arm64/kvm/mmu.c | 8 +++----- 1 file changed, 3 insertions(+), 5 deletions(-) diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c index d14504821b79..b7517c4a19c4 100644 --- a/arch/arm64/kvm/mmu.c +++ b/arch/arm64/kvm/mmu.c @@ -2028,17 +2028,15 @@ int kvm_arch_prepare_memory_region(struct kvm *kvm, if (!vma) break; - if (kvm_has_mte(kvm) && !kvm_vma_mte_allowed(vma)) { - ret = -EINVAL; - break; - } - if (vma->vm_flags & VM_PFNMAP) { /* IO region dirty page logging not allowed */ if (new->flags & KVM_MEM_LOG_DIRTY_PAGES) { ret = -EINVAL; break; } + } else if (kvm_has_mte(kvm) && !kvm_vma_mte_allowed(vma)) { + ret = -EINVAL; + break; } hva = min(reg_end, vma->vm_end); } while (hva < reg_end); -- 2.43.0
WARNING: multiple messages have this Message-ID (diff)
From: Alexandru Elisei <alexandru.elisei@arm.com> To: catalin.marinas@arm.com, will@kernel.org, oliver.upton@linux.dev, maz@kernel.org, james.morse@arm.com, suzuki.poulose@arm.com, yuzenghui@huawei.com, arnd@arndb.de, akpm@linux-foundation.org, mingo@redhat.com, peterz@infradead.org, juri.lelli@redhat.com, vincent.guittot@linaro.org, dietmar.eggemann@arm.com, rostedt@goodmis.org, bsegall@google.com, mgorman@suse.de, bristot@redhat.com, vschneid@redhat.com, mhiramat@kernel.org, rppt@kernel.org, hughd@google.com Cc: pcc@google.com, steven.price@arm.com, anshuman.khandual@arm.com, vincenzo.frascino@arm.com, david@redhat.com, eugenis@google.com, kcc@google.com, hyesoo.yu@samsung.com, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, kvmarm@lists.linux.dev, linux-fsdevel@vger.kernel.org, linux-arch@vger.kernel.org, linux-mm@kvack.org, linux-trace-kernel@vger.kernel.org Subject: [PATCH RFC v3 16/35] KVM: arm64: Don't deny VM_PFNMAP VMAs when kvm_has_mte() Date: Thu, 25 Jan 2024 16:42:37 +0000 [thread overview] Message-ID: <20240125164256.4147-17-alexandru.elisei@arm.com> (raw) In-Reply-To: <20240125164256.4147-1-alexandru.elisei@arm.com> According to ARM DDI 0487J.a, page D10-5976, a memory location which doesn't have the Normal memory attribute is considered Untagged, and accesses are Tag Unchecked. Tag reads from an Untagged address return 0b0000, and writes are ignored. Linux uses VM_PFNMAP VMAs represent device memory, and Linux doesn't set the VM_MTE_ALLOWED flag for these VMAs. In user_mem_abort(), KVM requires that all VMAs that back guest memory must allow tagging (VM_MTE_ALLOWED flag set), except for VMAs that represent device memory. When a memslot is created or changed, KVM enforces a different behaviour: **all** VMAs that intersect the memslot must allow tagging, even those that represent device memory. This is too restrictive, and can lead to inconsistent behaviour: a VM_PFNMAP VMA that is present when a memslot is created causes KVM_SET_USER_MEMORY_REGION to fail, but if such a VMA is created after the memslot has been created, the virtual machine will run without errors. Change kvm_arch_prepare_memory_region() to allow VM_PFNMAP VMAs when the VM has the MTE capability enabled. Signed-off-by: Alexandru Elisei <alexandru.elisei@arm.com> --- Changes from rfc v2: * New patch. It's a fix, and can be taken independently of the series. arch/arm64/kvm/mmu.c | 8 +++----- 1 file changed, 3 insertions(+), 5 deletions(-) diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c index d14504821b79..b7517c4a19c4 100644 --- a/arch/arm64/kvm/mmu.c +++ b/arch/arm64/kvm/mmu.c @@ -2028,17 +2028,15 @@ int kvm_arch_prepare_memory_region(struct kvm *kvm, if (!vma) break; - if (kvm_has_mte(kvm) && !kvm_vma_mte_allowed(vma)) { - ret = -EINVAL; - break; - } - if (vma->vm_flags & VM_PFNMAP) { /* IO region dirty page logging not allowed */ if (new->flags & KVM_MEM_LOG_DIRTY_PAGES) { ret = -EINVAL; break; } + } else if (kvm_has_mte(kvm) && !kvm_vma_mte_allowed(vma)) { + ret = -EINVAL; + break; } hva = min(reg_end, vma->vm_end); } while (hva < reg_end); -- 2.43.0 _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
next prev parent reply other threads:[~2024-01-25 16:44 UTC|newest] Thread overview: 190+ messages / expand[flat|nested] mbox.gz Atom feed top 2024-01-25 16:42 [PATCH RFC v3 00/35] Add support for arm64 MTE dynamic tag storage reuse Alexandru Elisei 2024-01-25 16:42 ` Alexandru Elisei 2024-01-25 16:42 ` [PATCH RFC v3 01/35] mm: page_alloc: Add gfp_flags parameter to arch_alloc_page() Alexandru Elisei 2024-01-25 16:42 ` Alexandru Elisei 2024-01-29 5:48 ` Anshuman Khandual 2024-01-29 5:48 ` Anshuman Khandual 2024-01-29 11:41 ` Alexandru Elisei 2024-01-29 11:41 ` Alexandru Elisei 2024-01-30 4:26 ` Anshuman Khandual 2024-01-30 4:26 ` Anshuman Khandual 2024-01-30 11:56 ` Alexandru Elisei 2024-01-30 11:56 ` Alexandru Elisei 2024-01-25 16:42 ` [PATCH RFC v3 02/35] mm: page_alloc: Add an arch hook early in free_pages_prepare() Alexandru Elisei 2024-01-25 16:42 ` Alexandru Elisei 2024-01-29 8:19 ` Anshuman Khandual 2024-01-29 8:19 ` Anshuman Khandual 2024-01-29 11:42 ` Alexandru Elisei 2024-01-29 11:42 ` Alexandru Elisei 2024-01-25 16:42 ` [PATCH RFC v3 03/35] mm: page_alloc: Add an arch hook to filter MIGRATE_CMA allocations Alexandru Elisei 2024-01-25 16:42 ` Alexandru Elisei 2024-01-29 8:44 ` Anshuman Khandual 2024-01-29 8:44 ` Anshuman Khandual 2024-01-29 11:45 ` Alexandru Elisei 2024-01-29 11:45 ` Alexandru Elisei 2024-01-25 16:42 ` [PATCH RFC v3 04/35] mm: page_alloc: Partially revert "mm: page_alloc: remove stale CMA guard code" Alexandru Elisei 2024-01-25 16:42 ` Alexandru Elisei 2024-01-29 9:01 ` Anshuman Khandual 2024-01-29 9:01 ` Anshuman Khandual 2024-01-29 11:46 ` Alexandru Elisei 2024-01-29 11:46 ` Alexandru Elisei 2024-01-30 4:34 ` Anshuman Khandual 2024-01-30 4:34 ` Anshuman Khandual 2024-01-30 11:57 ` Alexandru Elisei 2024-01-30 11:57 ` Alexandru Elisei 2024-01-31 3:27 ` Anshuman Khandual 2024-01-31 3:27 ` Anshuman Khandual 2024-01-25 16:42 ` [PATCH RFC v3 05/35] mm: cma: Don't append newline when generating CMA area name Alexandru Elisei 2024-01-25 16:42 ` Alexandru Elisei 2024-01-29 9:13 ` Anshuman Khandual 2024-01-29 9:13 ` Anshuman Khandual 2024-01-29 11:46 ` Alexandru Elisei 2024-01-29 11:46 ` Alexandru Elisei 2024-01-25 16:42 ` [PATCH RFC v3 06/35] mm: cma: Make CMA_ALLOC_SUCCESS/FAIL count the number of pages Alexandru Elisei 2024-01-25 16:42 ` Alexandru Elisei 2024-01-29 9:24 ` Anshuman Khandual 2024-01-29 9:24 ` Anshuman Khandual 2024-01-29 11:51 ` Alexandru Elisei 2024-01-29 11:51 ` Alexandru Elisei 2024-01-30 4:52 ` Anshuman Khandual 2024-01-30 4:52 ` Anshuman Khandual 2024-01-30 11:58 ` Alexandru Elisei 2024-01-30 11:58 ` Alexandru Elisei 2024-01-31 4:40 ` Anshuman Khandual 2024-01-31 4:40 ` Anshuman Khandual 2024-01-31 13:27 ` Alexandru Elisei 2024-01-31 13:27 ` Alexandru Elisei 2024-01-25 16:42 ` [PATCH RFC v3 07/35] mm: cma: Add CMA_RELEASE_{SUCCESS,FAIL} events Alexandru Elisei 2024-01-25 16:42 ` Alexandru Elisei 2024-01-29 9:31 ` Anshuman Khandual 2024-01-29 9:31 ` Anshuman Khandual 2024-01-29 11:53 ` Alexandru Elisei 2024-01-29 11:53 ` Alexandru Elisei 2024-01-31 5:59 ` Anshuman Khandual 2024-01-31 5:59 ` Anshuman Khandual 2024-01-25 16:42 ` [PATCH RFC v3 08/35] mm: cma: Introduce cma_alloc_range() Alexandru Elisei 2024-01-25 16:42 ` Alexandru Elisei 2024-01-30 5:20 ` Anshuman Khandual 2024-01-30 5:20 ` Anshuman Khandual 2024-01-30 11:35 ` Alexandru Elisei 2024-01-30 11:35 ` Alexandru Elisei 2024-01-31 6:24 ` Anshuman Khandual 2024-01-31 6:24 ` Anshuman Khandual 2024-01-31 14:18 ` Alexandru Elisei 2024-01-31 14:18 ` Alexandru Elisei 2024-01-25 16:42 ` [PATCH RFC v3 09/35] mm: cma: Introduce cma_remove_mem() Alexandru Elisei 2024-01-25 16:42 ` Alexandru Elisei 2024-01-30 5:50 ` Anshuman Khandual 2024-01-30 5:50 ` Anshuman Khandual 2024-01-30 11:33 ` Alexandru Elisei 2024-01-30 11:33 ` Alexandru Elisei 2024-01-31 13:19 ` Anshuman Khandual 2024-01-31 13:19 ` Anshuman Khandual 2024-01-31 13:48 ` Alexandru Elisei 2024-01-31 13:48 ` Alexandru Elisei 2024-01-25 16:42 ` [PATCH RFC v3 10/35] mm: cma: Fast track allocating memory when the pages are free Alexandru Elisei 2024-01-25 16:42 ` Alexandru Elisei 2024-01-30 9:18 ` Anshuman Khandual 2024-01-30 9:18 ` Anshuman Khandual 2024-01-30 11:34 ` Alexandru Elisei 2024-01-30 11:34 ` Alexandru Elisei 2024-01-25 16:42 ` [PATCH RFC v3 11/35] mm: Allow an arch to hook into folio allocation when VMA is known Alexandru Elisei 2024-01-25 16:42 ` Alexandru Elisei 2024-01-26 20:00 ` Peter Collingbourne 2024-01-26 20:00 ` Peter Collingbourne 2024-01-29 11:59 ` Alexandru Elisei 2024-01-29 11:59 ` Alexandru Elisei 2024-01-30 9:55 ` Anshuman Khandual 2024-01-30 9:55 ` Anshuman Khandual 2024-01-30 11:34 ` Alexandru Elisei 2024-01-30 11:34 ` Alexandru Elisei 2024-01-31 6:53 ` Anshuman Khandual 2024-01-31 6:53 ` Anshuman Khandual 2024-01-31 12:22 ` Alexandru Elisei 2024-01-31 12:22 ` Alexandru Elisei 2024-01-25 16:42 ` [PATCH RFC v3 12/35] mm: Call arch_swap_prepare_to_restore() before arch_swap_restore() Alexandru Elisei 2024-01-25 16:42 ` Alexandru Elisei 2024-02-01 3:30 ` Anshuman Khandual 2024-02-01 3:30 ` Anshuman Khandual 2024-02-01 17:32 ` Alexandru Elisei 2024-02-01 17:32 ` Alexandru Elisei 2024-01-25 16:42 ` [PATCH RFC v3 13/35] mm: memory: Introduce fault-on-access mechanism for pages Alexandru Elisei 2024-01-25 16:42 ` Alexandru Elisei 2024-02-01 5:52 ` Anshuman Khandual 2024-02-01 5:52 ` Anshuman Khandual 2024-02-01 17:36 ` Alexandru Elisei 2024-02-01 17:36 ` Alexandru Elisei 2024-01-25 16:42 ` [PATCH RFC v3 14/35] of: fdt: Return the region size in of_flat_dt_translate_address() Alexandru Elisei 2024-01-25 16:42 ` Alexandru Elisei 2024-01-25 16:42 ` [PATCH RFC v3 15/35] of: fdt: Add of_flat_read_u32() Alexandru Elisei 2024-01-25 16:42 ` Alexandru Elisei 2024-01-25 16:42 ` Alexandru Elisei [this message] 2024-01-25 16:42 ` [PATCH RFC v3 16/35] KVM: arm64: Don't deny VM_PFNMAP VMAs when kvm_has_mte() Alexandru Elisei 2024-01-25 16:42 ` [PATCH RFC v3 17/35] arm64: mte: Rework naming for tag manipulation functions Alexandru Elisei 2024-01-25 16:42 ` Alexandru Elisei 2024-01-25 16:42 ` [PATCH RFC v3 18/35] arm64: mte: Rename __GFP_ZEROTAGS to __GFP_TAGGED Alexandru Elisei 2024-01-25 16:42 ` Alexandru Elisei 2024-01-25 16:42 ` [PATCH RFC v3 19/35] arm64: mte: Discover tag storage memory Alexandru Elisei 2024-01-25 16:42 ` Alexandru Elisei 2024-01-26 8:50 ` Krzysztof Kozlowski 2024-01-26 8:50 ` Krzysztof Kozlowski 2024-01-26 17:01 ` Alexandru Elisei 2024-01-26 17:01 ` Alexandru Elisei 2024-01-25 16:42 ` [PATCH RFC v3 20/35] arm64: mte: Add tag storage memory to CMA Alexandru Elisei 2024-01-25 16:42 ` Alexandru Elisei 2024-01-25 16:42 ` [PATCH RFC v3 21/35] arm64: mte: Disable dynamic tag storage management if HW KASAN is enabled Alexandru Elisei 2024-01-25 16:42 ` Alexandru Elisei 2024-01-25 16:42 ` [PATCH RFC v3 22/35] arm64: mte: Enable tag storage if CMA areas have been activated Alexandru Elisei 2024-01-25 16:42 ` Alexandru Elisei 2024-02-02 22:30 ` Evgenii Stepanov 2024-02-02 22:30 ` Evgenii Stepanov 2024-02-05 16:30 ` Alexandru Elisei 2024-02-05 16:30 ` Alexandru Elisei 2024-01-25 16:42 ` [PATCH RFC v3 23/35] arm64: mte: Try to reserve tag storage in arch_alloc_page() Alexandru Elisei 2024-01-25 16:42 ` Alexandru Elisei 2024-01-30 0:04 ` Peter Collingbourne 2024-01-30 0:04 ` Peter Collingbourne 2024-01-30 11:38 ` Alexandru Elisei 2024-01-30 11:38 ` Alexandru Elisei 2024-01-25 16:42 ` [PATCH RFC v3 24/35] arm64: mte: Perform CMOs for tag blocks Alexandru Elisei 2024-01-25 16:42 ` Alexandru Elisei 2024-01-25 16:42 ` [PATCH RFC v3 25/35] arm64: mte: Reserve tag block for the zero page Alexandru Elisei 2024-01-25 16:42 ` Alexandru Elisei 2024-01-25 16:42 ` [PATCH RFC v3 26/35] arm64: mte: Use fault-on-access to reserve missing tag storage Alexandru Elisei 2024-01-25 16:42 ` Alexandru Elisei 2024-01-25 16:42 ` [PATCH RFC v3 27/35] arm64: mte: Handle tag storage pages mapped in an MTE VMA Alexandru Elisei 2024-01-25 16:42 ` Alexandru Elisei 2024-01-25 16:42 ` [PATCH RFC v3 28/35] arm64: mte: swap: Handle tag restoring when missing tag storage Alexandru Elisei 2024-01-25 16:42 ` Alexandru Elisei 2024-02-02 4:02 ` Peter Collingbourne 2024-02-02 4:02 ` Peter Collingbourne 2024-02-02 14:56 ` Alexandru Elisei 2024-02-02 14:56 ` Alexandru Elisei 2024-02-03 1:32 ` Evgenii Stepanov 2024-02-03 1:32 ` Evgenii Stepanov 2024-02-03 1:52 ` Peter Collingbourne 2024-02-03 1:52 ` Peter Collingbourne 2024-01-25 16:42 ` [PATCH RFC v3 29/35] arm64: mte: copypage: " Alexandru Elisei 2024-01-25 16:42 ` Alexandru Elisei 2024-01-25 16:42 ` [PATCH RFC v3 30/35] arm64: mte: ptrace: Handle pages with " Alexandru Elisei 2024-01-25 16:42 ` Alexandru Elisei 2024-02-01 9:21 ` Anshuman Khandual 2024-02-01 9:21 ` Anshuman Khandual 2024-02-01 17:38 ` Alexandru Elisei 2024-02-01 17:38 ` Alexandru Elisei 2024-01-25 16:42 ` [PATCH RFC v3 31/35] khugepaged: arm64: Don't collapse MTE enabled VMAs Alexandru Elisei 2024-01-25 16:42 ` Alexandru Elisei 2024-02-01 8:12 ` Anshuman Khandual 2024-02-01 8:12 ` Anshuman Khandual 2024-02-01 17:38 ` Alexandru Elisei 2024-02-01 17:38 ` Alexandru Elisei 2024-01-25 16:42 ` [PATCH RFC v3 32/35] KVM: arm64: mte: Reserve tag storage for virtual machines with MTE Alexandru Elisei 2024-01-25 16:42 ` Alexandru Elisei 2024-01-25 16:42 ` [PATCH RFC v3 33/35] KVM: arm64: mte: Introduce VM_MTE_KVM VMA flag Alexandru Elisei 2024-01-25 16:42 ` Alexandru Elisei 2024-01-25 16:42 ` [PATCH RFC v3 34/35] arm64: mte: Enable dynamic tag storage management Alexandru Elisei 2024-01-25 16:42 ` Alexandru Elisei 2024-01-25 16:42 ` [PATCH RFC v3 35/35] HACK! arm64: dts: Add fake tag storage to fvp-base-revc.dts Alexandru Elisei 2024-01-25 16:42 ` Alexandru Elisei 2024-01-25 17:01 ` [PATCH RFC v3 00/35] Add support for arm64 MTE dynamic tag storage reuse Steven Rostedt 2024-01-25 17:01 ` Steven Rostedt
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