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AJvYcCXWCoIllMA761J93FgJACB7bg0efZPmXZCq6AXDemZv6CS7a/KuTPD/V8FEcXFGBC3RQmTof5jfp9xek7rd04fRaYY=@vger.kernel.org X-Gm-Message-State: AOJu0Yxc0bo3aaZBsyJ7tfeZnJFeBc4M0JO2+2kKgldNgAD8XNoyhVa4 N5HsjNLZyzrkk4wy+TSm9585aR9d1SmMgQdvYKTbe2H9S1Wg7BfqIW9TiOWnOyVYpMQQdFzvXAY hMH0UuNCoooB9KLuopEc8RrlhqA== X-Received: from pfblh10.prod.google.com ([2002:a05:6a00:710a:b0:827:1713:6de8]) (user=ackerleytng job=prod-delivery.src-stubby-dispatcher) by 2002:a05:6a00:909e:b0:829:86a5:d30a with SMTP id d2e1a72fcca58-82c95d3979fmr158458b3a.16.1774563899156; Thu, 26 Mar 2026 15:24:59 -0700 (PDT) Date: Thu, 26 Mar 2026 15:24:26 -0700 In-Reply-To: <20260326-gmem-inplace-conversion-v4-0-e202fe950ffd@google.com> Precedence: bulk X-Mailing-List: linux-trace-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20260326-gmem-inplace-conversion-v4-0-e202fe950ffd@google.com> X-Developer-Key: i=ackerleytng@google.com; a=ed25519; pk=sAZDYXdm6Iz8FHitpHeFlCMXwabodTm7p8/3/8xUxuU= X-Developer-Signature: v=1; a=ed25519-sha256; t=1774563861; l=2856; i=ackerleytng@google.com; s=20260225; h=from:subject:message-id; bh=YkFqhRwEQZVyHiDJUj6H4E4tU4Wvsdzaj7skS/qkZuE=; b=fYqOIs0iI3/nAEboIQ/PrkKD3DqiKgh0ZKOH0/alwG+ByCa4bQDdDE7B7eewnHx+Vkr5yyN3L qYWooCrUe9JDhY0cerupGdZo3deYAs2/zlmrWXsG3XBYe8lS1/Lli9y X-Mailer: b4 0.14.3 Message-ID: <20260326-gmem-inplace-conversion-v4-17-e202fe950ffd@google.com> Subject: [PATCH RFC v4 17/44] KVM: Let userspace disable per-VM mem attributes, enable per-gmem attributes From: Ackerley Tng To: aik@amd.com, andrew.jones@linux.dev, binbin.wu@linux.intel.com, brauner@kernel.org, chao.p.peng@linux.intel.com, david@kernel.org, ira.weiny@intel.com, jmattson@google.com, jroedel@suse.de, jthoughton@google.com, michael.roth@amd.com, oupton@kernel.org, pankaj.gupta@amd.com, qperret@google.com, rick.p.edgecombe@intel.com, rientjes@google.com, shivankg@amd.com, steven.price@arm.com, tabba@google.com, willy@infradead.org, wyihan@google.com, yan.y.zhao@intel.com, forkloop@google.com, pratyush@kernel.org, suzuki.poulose@arm.com, aneesh.kumar@kernel.org, Paolo Bonzini , Sean Christopherson , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , x86@kernel.org, "H. Peter Anvin" , Steven Rostedt , Masami Hiramatsu , Mathieu Desnoyers , Jonathan Corbet , Shuah Khan , Shuah Khan , Vishal Annapurve , Andrew Morton , Chris Li , Kairui Song , Kemeng Shi , Nhat Pham , Baoquan He , Barry Song , Axel Rasmussen , Yuanchu Xie , Wei Xu , Jason Gunthorpe , Vlastimil Babka Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org, linux-doc@vger.kernel.org, linux-kselftest@vger.kernel.org, linux-mm@kvack.org, Ackerley Tng Content-Type: text/plain; charset="utf-8" From: Sean Christopherson Make vm_memory_attributes a module parameter so that userspace can disable the use of memory attributes on the VM level. To avoid inconsistencies in the way memory attributes are tracked in KVM and guest_memfd, the vm_memory_attributes module_param is made read-only (0444). Make CONFIG_KVM_VM_MEMORY_ATTRIBUTES selectable, only for (CoCo) VM types that might use vm_memory_attributes. Signed-off-by: Sean Christopherson Signed-off-by: Ackerley Tng --- arch/x86/kvm/Kconfig | 13 +++++++++---- virt/kvm/kvm_main.c | 1 + 2 files changed, 10 insertions(+), 4 deletions(-) diff --git a/arch/x86/kvm/Kconfig b/arch/x86/kvm/Kconfig index b6d65ee664d0f..8b97d341bd33f 100644 --- a/arch/x86/kvm/Kconfig +++ b/arch/x86/kvm/Kconfig @@ -82,13 +82,20 @@ config KVM_WERROR config KVM_VM_MEMORY_ATTRIBUTES select KVM_MEMORY_ATTRIBUTES - bool + depends on KVM_SW_PROTECTED_VM || KVM_INTEL_TDX || KVM_AMD_SEV + bool "Enable per-VM memory attributes (for CoCo VMs)" + help + Enable support for per-VM memory attributes, which are deprecated in + favor of tracking memory attributes in guest_memfd. Select this if + you need to run CoCo VMs using a VMM that doesn't support guest_memfd + memory attributes. + + If unsure, say N. config KVM_SW_PROTECTED_VM bool "Enable support for KVM software-protected VMs" depends on EXPERT depends on KVM_X86 && X86_64 - select KVM_VM_MEMORY_ATTRIBUTES help Enable support for KVM software-protected VMs. Currently, software- protected VMs are purely a development and testing vehicle for @@ -139,7 +146,6 @@ config KVM_INTEL_TDX bool "Intel Trust Domain Extensions (TDX) support" default y depends on INTEL_TDX_HOST - select KVM_VM_MEMORY_ATTRIBUTES select HAVE_KVM_ARCH_GMEM_POPULATE help Provides support for launching Intel Trust Domain Extensions (TDX) @@ -163,7 +169,6 @@ config KVM_AMD_SEV depends on KVM_AMD && X86_64 depends on CRYPTO_DEV_SP_PSP && !(KVM_AMD=y && CRYPTO_DEV_CCP_DD=m) select ARCH_HAS_CC_PLATFORM - select KVM_VM_MEMORY_ATTRIBUTES select HAVE_KVM_ARCH_GMEM_PREPARE select HAVE_KVM_ARCH_GMEM_INVALIDATE select HAVE_KVM_ARCH_GMEM_POPULATE diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index 6607127eaaeed..05e203f5292be 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -105,6 +105,7 @@ module_param(allow_unsafe_mappings, bool, 0444); #ifdef CONFIG_KVM_MEMORY_ATTRIBUTES #ifdef CONFIG_KVM_VM_MEMORY_ATTRIBUTES bool vm_memory_attributes = true; +module_param(vm_memory_attributes, bool, 0444); #endif DEFINE_STATIC_CALL_RET0(__kvm_get_memory_attributes, kvm_get_memory_attributes_t); EXPORT_SYMBOL_FOR_KVM_INTERNAL(STATIC_CALL_KEY(__kvm_get_memory_attributes)); -- 2.53.0.1018.g2bb0e51243-goog