linux-kernel - [PATCH v7 1/5] KVM: arm64: Rename symbols to reflect whether CMO may be used

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20250618065541.50049-2-ankita@nvidia.com>
Date: Wed, 18 Jun 2025 06:55:37 +0000
From: <ankita@...dia.com>
To: <ankita@...dia.com>, <jgg@...dia.com>, <maz@...nel.org>,
	<oliver.upton@...ux.dev>, <joey.gouly@....com>, <suzuki.poulose@....com>,
	<yuzenghui@...wei.com>, <catalin.marinas@....com>, <will@...nel.org>,
	<ryan.roberts@....com>, <shahuang@...hat.com>, <lpieralisi@...nel.org>,
	<david@...hat.com>, <ddutile@...hat.com>, <seanjc@...gle.com>
CC: <aniketa@...dia.com>, <cjia@...dia.com>, <kwankhede@...dia.com>,
	<kjaju@...dia.com>, <targupta@...dia.com>, <vsethi@...dia.com>,
	<acurrid@...dia.com>, <apopple@...dia.com>, <jhubbard@...dia.com>,
	<danw@...dia.com>, <zhiw@...dia.com>, <mochs@...dia.com>,
	<udhoke@...dia.com>, <dnigam@...dia.com>, <alex.williamson@...hat.com>,
	<sebastianene@...gle.com>, <coltonlewis@...gle.com>, <kevin.tian@...el.com>,
	<yi.l.liu@...el.com>, <ardb@...nel.org>, <akpm@...ux-foundation.org>,
	<gshan@...hat.com>, <linux-mm@...ck.org>, <tabba@...gle.com>,
	<qperret@...gle.com>, <kvmarm@...ts.linux.dev>,
	<linux-kernel@...r.kernel.org>, <linux-arm-kernel@...ts.infradead.org>,
	<maobibo@...ngson.cn>
Subject: [PATCH v7 1/5] KVM: arm64: Rename symbols to reflect whether CMO may be used

From: Ankit Agrawal <ankita@...dia.com>

Currently, the kvm_is_device_pfn() detects if the memory is kernel
mapped. It thus implies whether KVM can use Cache Maintenance
Operations (CMOs) on that PFN. Rename the function to reflect this.

Additionally, the "device" variable is effectively trying to setup the S2
to prevent CMOs. Calling it 'disable_cmo' would make this code clearer.

Suggested-by: Jason Gunthorpe <jgg@...dia.com>
Signed-off-by: Ankit Agrawal <ankita@...dia.com>
---
 arch/arm64/kvm/mmu.c | 18 +++++++++---------
 1 file changed, 9 insertions(+), 9 deletions(-)

diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c
index 2942ec92c5a4..3d77a278fc4f 100644
--- a/arch/arm64/kvm/mmu.c
+++ b/arch/arm64/kvm/mmu.c
@@ -193,9 +193,9 @@ int kvm_arch_flush_remote_tlbs_range(struct kvm *kvm,
 	return 0;
 }
 
-static bool kvm_is_device_pfn(unsigned long pfn)
+static bool kvm_can_use_cmo_pfn(unsigned long pfn)
 {
-	return !pfn_is_map_memory(pfn);
+	return pfn_is_map_memory(pfn);
 }
 
 static void *stage2_memcache_zalloc_page(void *arg)
@@ -1478,7 +1478,7 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa,
 	int ret = 0;
 	bool write_fault, writable, force_pte = false;
 	bool exec_fault, mte_allowed;
-	bool device = false, vfio_allow_any_uc = false;
+	bool disable_cmo = false, vfio_allow_any_uc = false;
 	unsigned long mmu_seq;
 	phys_addr_t ipa = fault_ipa;
 	struct kvm *kvm = vcpu->kvm;
@@ -1642,7 +1642,7 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa,
 	if (is_error_noslot_pfn(pfn))
 		return -EFAULT;
 
-	if (kvm_is_device_pfn(pfn)) {
+	if (!kvm_can_use_cmo_pfn(pfn)) {
 		/*
 		 * If the page was identified as device early by looking at
 		 * the VMA flags, vma_pagesize is already representing the
@@ -1653,7 +1653,7 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa,
 		 * In both cases, we don't let transparent_hugepage_adjust()
 		 * change things at the last minute.
 		 */
-		device = true;
+		disable_cmo = true;
 	} else if (logging_active && !write_fault) {
 		/*
 		 * Only actually map the page as writable if this was a write
@@ -1662,7 +1662,7 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa,
 		writable = false;
 	}
 
-	if (exec_fault && device)
+	if (exec_fault && disable_cmo)
 		return -ENOEXEC;
 
 	/*
@@ -1695,7 +1695,7 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa,
 	 * If we are not forced to use page mapping, check if we are
 	 * backed by a THP and thus use block mapping if possible.
 	 */
-	if (vma_pagesize == PAGE_SIZE && !(force_pte || device)) {
+	if (vma_pagesize == PAGE_SIZE && !(force_pte || disable_cmo)) {
 		if (fault_is_perm && fault_granule > PAGE_SIZE)
 			vma_pagesize = fault_granule;
 		else
@@ -1709,7 +1709,7 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa,
 		}
 	}
 
-	if (!fault_is_perm && !device && kvm_has_mte(kvm)) {
+	if (!fault_is_perm && !disable_cmo && kvm_has_mte(kvm)) {
 		/* Check the VMM hasn't introduced a new disallowed VMA */
 		if (mte_allowed) {
 			sanitise_mte_tags(kvm, pfn, vma_pagesize);
@@ -1725,7 +1725,7 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa,
 	if (exec_fault)
 		prot |= KVM_PGTABLE_PROT_X;
 
-	if (device) {
+	if (disable_cmo) {
 		if (vfio_allow_any_uc)
 			prot |= KVM_PGTABLE_PROT_NORMAL_NC;
 		else
-- 
2.34.1