From: Sean Christopherson <seanjc@google•com>
To: Paolo Bonzini <pbonzini@redhat•com>,
Marc Zyngier <maz@kernel•org>,
Oliver Upton <oliver.upton@linux•dev>,
Sean Christopherson <seanjc@google•com>
Cc: kvm@vger•kernel.org, linux-arm-kernel@lists•infradead.org,
kvmarm@lists•linux.dev, linux-kernel@vger•kernel.org,
Ira Weiny <ira.weiny@intel•com>, Gavin Shan <gshan@redhat•com>,
Shivank Garg <shivankg@amd•com>,
Vlastimil Babka <vbabka@suse•cz>,
Xiaoyao Li <xiaoyao.li@intel•com>,
David Hildenbrand <david@redhat•com>,
Fuad Tabba <tabba@google•com>,
Ackerley Tng <ackerleytng@google•com>,
Tao Chan <chentao@kylinos•cn>,
James Houghton <jthoughton@google•com>
Subject: [PATCH v17 09/24] KVM: x86: Enable KVM_GUEST_MEMFD for all 64-bit builds
Date: Tue, 29 Jul 2025 15:54:40 -0700 [thread overview]
Message-ID: <20250729225455.670324-10-seanjc@google.com> (raw)
In-Reply-To: <20250729225455.670324-1-seanjc@google.com>
From: Fuad Tabba <tabba@google•com>
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 <seanjc@google•com>
Signed-off-by: Fuad Tabba <tabba@google•com>
Reviewed-by: Xiaoyao Li <xiaoyao.li@intel•com>
Reviewed-by: David Hildenbrand <david@redhat•com>
Signed-off-by: Sean Christopherson <seanjc@google•com>
---
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;
--
2.50.1.552.g942d659e1b-goog
next prev parent reply other threads:[~2025-07-29 23:22 UTC|newest]
Thread overview: 58+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-07-29 22:54 [PATCH v17 00/24] KVM: Enable mmap() for guest_memfd Sean Christopherson
2025-07-29 22:54 ` [PATCH v17 01/24] KVM: Rename CONFIG_KVM_PRIVATE_MEM to CONFIG_KVM_GUEST_MEMFD Sean Christopherson
2025-07-29 22:54 ` [PATCH v17 02/24] KVM: x86: Have all vendor neutral sub-configs depend on KVM_X86, not just KVM Sean Christopherson
2025-07-31 8:08 ` Fuad Tabba
2025-07-29 22:54 ` [PATCH v17 03/24] KVM: x86: Select KVM_GENERIC_PRIVATE_MEM directly from KVM_SW_PROTECTED_VM Sean Christopherson
2025-07-31 8:08 ` Fuad Tabba
2025-07-29 22:54 ` [PATCH v17 04/24] KVM: x86: Select TDX's KVM_GENERIC_xxx dependencies iff CONFIG_KVM_INTEL_TDX=y Sean Christopherson
2025-07-31 8:07 ` Fuad Tabba
2025-07-29 22:54 ` [PATCH v17 05/24] KVM: Rename CONFIG_KVM_GENERIC_PRIVATE_MEM to CONFIG_HAVE_KVM_ARCH_GMEM_POPULATE Sean Christopherson
2025-07-29 22:54 ` [PATCH v17 06/24] KVM: Rename kvm_slot_can_be_private() to kvm_slot_has_gmem() Sean Christopherson
2025-07-29 22:54 ` [PATCH v17 07/24] KVM: Fix comments that refer to slots_lock Sean Christopherson
2025-07-29 22:54 ` [PATCH v17 08/24] KVM: Fix comment that refers to kvm uapi header path Sean Christopherson
2025-07-29 22:54 ` Sean Christopherson [this message]
2025-07-29 22:54 ` [PATCH v17 10/24] KVM: guest_memfd: Add plumbing to host to map guest_memfd pages Sean Christopherson
2025-07-29 22:54 ` [PATCH v17 11/24] KVM: guest_memfd: Track guest_memfd mmap support in memslot Sean Christopherson
2025-07-29 22:54 ` [PATCH v17 12/24] KVM: x86/mmu: Rename .private_max_mapping_level() to .gmem_max_mapping_level() Sean Christopherson
2025-07-31 8:15 ` Fuad Tabba
2025-07-31 8:29 ` David Hildenbrand
2025-07-31 8:33 ` Fuad Tabba
2025-07-29 22:54 ` [PATCH v17 13/24] KVM: x86/mmu: Hoist guest_memfd max level/order helpers "up" in mmu.c Sean Christopherson
2025-07-31 7:59 ` David Hildenbrand
2025-07-31 8:06 ` Fuad Tabba
2025-07-29 22:54 ` [PATCH v17 14/24] KVM: x86/mmu: Enforce guest_memfd's max order when recovering hugepages Sean Christopherson
2025-07-30 7:33 ` Xiaoyao Li
2025-07-31 8:06 ` David Hildenbrand
2025-07-31 8:10 ` Fuad Tabba
2025-07-29 22:54 ` [PATCH v17 15/24] KVM: x86/mmu: Extend guest_memfd's max mapping level to shared mappings Sean Christopherson
2025-07-30 7:36 ` Xiaoyao Li
2025-07-31 8:01 ` David Hildenbrand
2025-07-31 8:05 ` Fuad Tabba
2025-07-29 22:54 ` [PATCH v17 16/24] KVM: x86/mmu: Handle guest page faults for guest_memfd with shared memory Sean Christopherson
2025-07-30 7:37 ` Xiaoyao Li
2025-07-29 22:54 ` [PATCH v17 17/24] KVM: arm64: Refactor user_mem_abort() Sean Christopherson
2025-07-29 22:54 ` [PATCH v17 18/24] KVM: arm64: Handle guest_memfd-backed guest page faults Sean Christopherson
2025-07-29 22:54 ` [PATCH v17 19/24] KVM: arm64: nv: Handle VNCR_EL2-triggered faults backed by guest_memfd Sean Christopherson
2025-07-29 22:54 ` [PATCH v17 20/24] KVM: arm64: Enable support for guest_memfd backed memory Sean Christopherson
2025-07-29 22:54 ` [PATCH v17 21/24] KVM: Allow and advertise support for host mmap() on guest_memfd files Sean Christopherson
2025-07-29 22:54 ` [PATCH v17 22/24] KVM: selftests: Do not use hardcoded page sizes in guest_memfd test Sean Christopherson
2025-07-30 11:04 ` Xiaoyao Li
2025-07-29 22:54 ` [PATCH v17 23/24] KVM: selftests: guest_memfd mmap() test when mmap is supported Sean Christopherson
2025-07-30 11:39 ` Xiaoyao Li
2025-07-30 12:57 ` Sean Christopherson
2025-07-31 7:49 ` Xiaoyao Li
2025-08-07 8:12 ` Shivank Garg
2025-07-29 22:54 ` [PATCH v17 24/24] KVM: selftests: Add guest_memfd testcase to fault-in on !mmap()'d memory Sean Christopherson
2025-07-30 8:20 ` Xiaoyao Li
2025-07-30 15:51 ` Fuad Tabba
2026-03-30 6:21 ` Zenghui Yu
2026-04-17 16:47 ` Sean Christopherson
2026-05-12 7:28 ` Zenghui Yu
2026-05-12 15:53 ` Sean Christopherson
2025-07-30 21:34 ` [PATCH v17 00/24] KVM: Enable mmap() for guest_memfd Ackerley Tng
2025-07-30 22:44 ` Ackerley Tng
2025-08-27 8:43 ` Paolo Bonzini
2025-08-27 12:57 ` Sean Christopherson
2025-08-27 13:08 ` Marc Zyngier
2025-08-27 13:11 ` Paolo Bonzini
2025-08-27 13:14 ` Marc Zyngier
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