From: "Aneesh Kumar K.V (Arm)" <aneesh.kumar@kernel.org>
To: linux-kernel@vger.kernel.org,
linux-arm-kernel@lists.infradead.org, kvmarm@lists.linux.dev
Cc: Suzuki K Poulose <Suzuki.Poulose@arm.com>,
Steven Price <steven.price@arm.com>,
Will Deacon <will@kernel.org>,
Catalin Marinas <catalin.marinas@arm.com>,
Marc Zyngier <maz@kernel.org>,
Mark Rutland <mark.rutland@arm.com>,
Oliver Upton <oliver.upton@linux.dev>,
Joey Gouly <joey.gouly@arm.com>,
Zenghui Yu <yuzenghui@huawei.com>,
"Aneesh Kumar K.V (Arm)" <aneesh.kumar@kernel.org>
Subject: [PATCH 3/4] arm64: mte: update code comments
Date: Mon, 28 Oct 2024 15:10:13 +0530 [thread overview]
Message-ID: <20241028094014.2596619-4-aneesh.kumar@kernel.org> (raw)
In-Reply-To: <20241028094014.2596619-1-aneesh.kumar@kernel.org>
commit d77e59a8fccd ("arm64: mte: Lock a page for MTE tag
initialisation") updated the locking such the kernel now allows
VM_SHARED mapping with MTE. Update the code comment to reflect this.
Signed-off-by: Aneesh Kumar K.V (Arm) <aneesh.kumar@kernel.org>
---
arch/arm64/kvm/mmu.c | 12 ++++++------
1 file changed, 6 insertions(+), 6 deletions(-)
diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c
index a509b63bd4dd..b5824e93cee0 100644
--- a/arch/arm64/kvm/mmu.c
+++ b/arch/arm64/kvm/mmu.c
@@ -1390,11 +1390,8 @@ static int get_vma_page_shift(struct vm_area_struct *vma, unsigned long hva)
* able to see the page's tags and therefore they must be initialised first. If
* PG_mte_tagged is set, tags have already been initialised.
*
- * The race in the test/set of the PG_mte_tagged flag is handled by:
- * - preventing VM_SHARED mappings in a memslot with MTE preventing two VMs
- * racing to santise the same page
- * - mmap_lock protects between a VM faulting a page in and the VMM performing
- * an mprotect() to add VM_MTE
+ * The race in the test/set of the PG_mte_tagged flag is handled by
+ * using PG_mte_lock and PG_mte_tagged together.
*/
static void sanitise_mte_tags(struct kvm *kvm, kvm_pfn_t pfn,
unsigned long size)
@@ -1646,7 +1643,10 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa,
}
if (!fault_is_perm && !device && kvm_has_mte(kvm)) {
- /* Check the VMM hasn't introduced a new disallowed VMA */
+ /*
+ * not a permission fault implies a translation fault which
+ * means mapping the page for the first time
+ */
if (mte_allowed) {
sanitise_mte_tags(kvm, pfn, vma_pagesize);
} else {
--
2.43.0
next prev parent reply other threads:[~2024-10-28 11:00 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-10-28 9:40 [PATCH 0/4] Add support for NoTagAccess memory attribute Aneesh Kumar K.V (Arm)
2024-10-28 9:40 ` [PATCH 1/4] arm64: Update the values to binary from hex Aneesh Kumar K.V (Arm)
2024-10-28 9:40 ` [PATCH 2/4] arm64: cpufeature: add Allocation Tag Access Permission (MTE_PERM) feature Aneesh Kumar K.V (Arm)
2024-10-28 9:40 ` Aneesh Kumar K.V (Arm) [this message]
2024-10-28 10:33 ` [PATCH 3/4] arm64: mte: update code comments Marc Zyngier
2024-10-28 12:47 ` Aneesh Kumar K.V
2024-10-28 18:09 ` Marc Zyngier
2024-10-28 9:40 ` [PATCH 4/4] arm64: mte: Use stage-2 NoTagAccess memory attribute if supported Aneesh Kumar K.V (Arm)
2024-10-28 10:54 ` Marc Zyngier
2024-10-28 13:28 ` Aneesh Kumar K.V
2024-10-28 18:37 ` Marc Zyngier
2024-11-08 7:59 ` Aneesh Kumar K.V
2024-11-12 11:51 ` Marc Zyngier
2024-11-15 16:23 ` Catalin Marinas
2024-10-28 14:44 ` Oliver Upton
2024-10-28 14:52 ` Aneesh Kumar K.V
2024-10-28 15:07 ` Oliver Upton
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