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AJvYcCWNdDQp5fLxDWA/Vf0jrmmi0yfV6NST9NUozwTvqesoAYx+gBLiWGK+rxVLa5xphHJTV9vHhSc=@lists.linux.dev X-Gm-Message-State: AOJu0YzVTHEHf2DFGV8m/GOxXtezK5CyCXYY5k91mOrFvgKueG8SK3Np N+ww0sZZDmpUjuMmu04569gBDZ6zL/fvlEjhIrd5MxIWvSpMUyQ7dqOe/cK/9h3b6zbNisIHKDy 2Mg== X-Google-Smtp-Source: AGHT+IHLzuLINdJSWTguMGiWOg3ozLl75dp1Qprfo0bHjzS8AWsGSIsnNSxbTc+BmMB/sQkP4J6w00TZ8w== X-Received: from wrjb12.prod.google.com ([2002:adf:e30c:0:b0:3a4:e3a1:4e8e]) (user=tabba job=prod-delivery.src-stubby-dispatcher) by 2002:a5d:64c5:0:b0:3a5:5270:a52c with SMTP id ffacd0b85a97d-3b768c6cbf4mr2019207f8f.0.1753267644477; Wed, 23 Jul 2025 03:47:24 -0700 (PDT) Date: Wed, 23 Jul 2025 11:47:01 +0100 In-Reply-To: <20250723104714.1674617-1-tabba@google.com> Precedence: bulk X-Mailing-List: kvmarm@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20250723104714.1674617-1-tabba@google.com> X-Mailer: git-send-email 2.50.1.470.g6ba607880d-goog Message-ID: <20250723104714.1674617-10-tabba@google.com> Subject: [PATCH v16 09/22] KVM: x86: Enable KVM_GUEST_MEMFD for all 64-bit builds From: Fuad Tabba To: kvm@vger.kernel.org, linux-arm-msm@vger.kernel.org, linux-mm@kvack.org, kvmarm@lists.linux.dev Cc: pbonzini@redhat.com, chenhuacai@kernel.org, mpe@ellerman.id.au, anup@brainfault.org, paul.walmsley@sifive.com, palmer@dabbelt.com, aou@eecs.berkeley.edu, seanjc@google.com, viro@zeniv.linux.org.uk, brauner@kernel.org, willy@infradead.org, akpm@linux-foundation.org, xiaoyao.li@intel.com, yilun.xu@intel.com, chao.p.peng@linux.intel.com, jarkko@kernel.org, amoorthy@google.com, dmatlack@google.com, isaku.yamahata@intel.com, mic@digikod.net, vbabka@suse.cz, vannapurve@google.com, ackerleytng@google.com, mail@maciej.szmigiero.name, david@redhat.com, michael.roth@amd.com, wei.w.wang@intel.com, liam.merwick@oracle.com, isaku.yamahata@gmail.com, kirill.shutemov@linux.intel.com, suzuki.poulose@arm.com, steven.price@arm.com, quic_eberman@quicinc.com, quic_mnalajal@quicinc.com, quic_tsoni@quicinc.com, quic_svaddagi@quicinc.com, quic_cvanscha@quicinc.com, quic_pderrin@quicinc.com, quic_pheragu@quicinc.com, catalin.marinas@arm.com, james.morse@arm.com, yuzenghui@huawei.com, oliver.upton@linux.dev, maz@kernel.org, will@kernel.org, qperret@google.com, keirf@google.com, roypat@amazon.co.uk, shuah@kernel.org, hch@infradead.org, jgg@nvidia.com, rientjes@google.com, jhubbard@nvidia.com, fvdl@google.com, hughd@google.com, jthoughton@google.com, peterx@redhat.com, pankaj.gupta@amd.com, ira.weiny@intel.com, tabba@google.com Content-Type: text/plain; charset="UTF-8" Enable KVM_GUEST_MEMFD for all KVM x86 64-bit builds, i.e. for "default" VM types when running on 64-bit KVM. This will allow using guest_memfd to back non-private memory for all VM shapes, by supporting mmap() on guest_memfd. Opportunistically clean up various conditionals that become tautologies once x86 selects KVM_GUEST_MEMFD more broadly. Specifically, because SW protected VMs, SEV, and TDX are all 64-bit only, private memory no longer needs to take explicit dependencies on KVM_GUEST_MEMFD, because it is effectively a prerequisite. Suggested-by: Sean Christopherson Signed-off-by: Fuad Tabba --- arch/x86/include/asm/kvm_host.h | 4 +--- arch/x86/kvm/Kconfig | 12 ++++-------- include/linux/kvm_host.h | 9 ++------- virt/kvm/kvm_main.c | 4 ++-- 4 files changed, 9 insertions(+), 20 deletions(-) diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h index 7b0f2b3e492d..50366a1ca192 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -2276,10 +2276,8 @@ void kvm_configure_mmu(bool enable_tdp, int tdp_forced_root_level, int tdp_max_root_level, int tdp_huge_page_level); -#ifdef CONFIG_KVM_GUEST_MEMFD +#ifdef CONFIG_KVM_GENERIC_MEMORY_ATTRIBUTES #define kvm_arch_has_private_mem(kvm) ((kvm)->arch.has_private_mem) -#else -#define kvm_arch_has_private_mem(kvm) false #endif #define kvm_arch_has_readonly_mem(kvm) (!(kvm)->arch.has_protected_state) diff --git a/arch/x86/kvm/Kconfig b/arch/x86/kvm/Kconfig index c763446d9b9f..4e43923656d0 100644 --- a/arch/x86/kvm/Kconfig +++ b/arch/x86/kvm/Kconfig @@ -47,6 +47,7 @@ config KVM_X86 select KVM_GENERIC_HARDWARE_ENABLING select KVM_GENERIC_PRE_FAULT_MEMORY select KVM_WERROR if WERROR + select KVM_GUEST_MEMFD if X86_64 config KVM tristate "Kernel-based Virtual Machine (KVM) support" @@ -79,16 +80,11 @@ config KVM_WERROR If in doubt, say "N". -config KVM_X86_PRIVATE_MEM - select KVM_GENERIC_MEMORY_ATTRIBUTES - select KVM_GUEST_MEMFD - bool - config KVM_SW_PROTECTED_VM bool "Enable support for KVM software-protected VMs" depends on EXPERT depends on KVM_X86 && X86_64 - select KVM_X86_PRIVATE_MEM + select KVM_GENERIC_MEMORY_ATTRIBUTES help Enable support for KVM software-protected VMs. Currently, software- protected VMs are purely a development and testing vehicle for @@ -138,7 +134,7 @@ config KVM_INTEL_TDX bool "Intel Trust Domain Extensions (TDX) support" default y depends on INTEL_TDX_HOST - select KVM_X86_PRIVATE_MEM + select KVM_GENERIC_MEMORY_ATTRIBUTES select HAVE_KVM_ARCH_GMEM_POPULATE help Provides support for launching Intel Trust Domain Extensions (TDX) @@ -162,7 +158,7 @@ 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_X86_PRIVATE_MEM + select KVM_GENERIC_MEMORY_ATTRIBUTES select HAVE_KVM_ARCH_GMEM_PREPARE select HAVE_KVM_ARCH_GMEM_INVALIDATE select HAVE_KVM_ARCH_GMEM_POPULATE diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h index 56ea8c862cfd..4d1c44622056 100644 --- a/include/linux/kvm_host.h +++ b/include/linux/kvm_host.h @@ -719,11 +719,7 @@ static inline int kvm_arch_vcpu_memslots_id(struct kvm_vcpu *vcpu) } #endif -/* - * Arch code must define kvm_arch_has_private_mem if support for guest_memfd is - * enabled. - */ -#if !defined(kvm_arch_has_private_mem) && !IS_ENABLED(CONFIG_KVM_GUEST_MEMFD) +#ifndef CONFIG_KVM_GENERIC_MEMORY_ATTRIBUTES static inline bool kvm_arch_has_private_mem(struct kvm *kvm) { return false; @@ -2505,8 +2501,7 @@ bool kvm_arch_post_set_memory_attributes(struct kvm *kvm, static inline bool kvm_mem_is_private(struct kvm *kvm, gfn_t gfn) { - return IS_ENABLED(CONFIG_KVM_GUEST_MEMFD) && - kvm_get_memory_attributes(kvm, gfn) & KVM_MEMORY_ATTRIBUTE_PRIVATE; + return kvm_get_memory_attributes(kvm, gfn) & KVM_MEMORY_ATTRIBUTE_PRIVATE; } #else static inline bool kvm_mem_is_private(struct kvm *kvm, gfn_t gfn) diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index aa86dfd757db..4f57cb92e109 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -1588,7 +1588,7 @@ static int check_memory_region_flags(struct kvm *kvm, { u32 valid_flags = KVM_MEM_LOG_DIRTY_PAGES; - if (kvm_arch_has_private_mem(kvm)) + if (IS_ENABLED(CONFIG_KVM_GUEST_MEMFD)) valid_flags |= KVM_MEM_GUEST_MEMFD; /* Dirty logging private memory is not currently supported. */ @@ -4917,7 +4917,7 @@ static int kvm_vm_ioctl_check_extension_generic(struct kvm *kvm, long arg) #endif #ifdef CONFIG_KVM_GUEST_MEMFD case KVM_CAP_GUEST_MEMFD: - return !kvm || kvm_arch_has_private_mem(kvm); + return 1; #endif default: break; -- 2.50.1.470.g6ba607880d-goog