From 19a9a1ab5c3dce65fff4ac50700117039c23d525 Mon Sep 17 00:00:00 2001 From: Fuad Tabba Date: Tue, 29 Jul 2025 15:54:32 -0700 Subject: KVM: Rename CONFIG_KVM_PRIVATE_MEM to CONFIG_KVM_GUEST_MEMFD Rename the Kconfig option CONFIG_KVM_PRIVATE_MEM to CONFIG_KVM_GUEST_MEMFD. The original name implied that the feature only supported "private" memory. However, CONFIG_KVM_PRIVATE_MEM enables guest_memfd in general, which is not exclusively for private memory. Subsequent patches in this series will add guest_memfd support for non-CoCo VMs, whose memory is not private. Renaming the Kconfig option to CONFIG_KVM_GUEST_MEMFD more accurately reflects its broader scope as the main Kconfig option for all guest_memfd-backed memory. This provides clearer semantics for the option and avoids confusion as new features are introduced. Reviewed-by: Ira Weiny Reviewed-by: Gavin Shan Reviewed-by: Shivank Garg Reviewed-by: Vlastimil Babka Reviewed-by: Xiaoyao Li Co-developed-by: David Hildenbrand Signed-off-by: David Hildenbrand Signed-off-by: Fuad Tabba Signed-off-by: Sean Christopherson Message-ID: <20250729225455.670324-2-seanjc@google.com> Signed-off-by: Paolo Bonzini --- include/linux/kvm_host.h | 14 +++++++------- 1 file changed, 7 insertions(+), 7 deletions(-) (limited to 'include/linux/kvm_host.h') diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h index 15656b7fba6c..8cdc0b3cc1b1 100644 --- a/include/linux/kvm_host.h +++ b/include/linux/kvm_host.h @@ -602,7 +602,7 @@ struct kvm_memory_slot { short id; u16 as_id; -#ifdef CONFIG_KVM_PRIVATE_MEM +#ifdef CONFIG_KVM_GUEST_MEMFD struct { /* * Writes protected by kvm->slots_lock. Acquiring a @@ -720,10 +720,10 @@ 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 private memory - * is enabled. + * 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_PRIVATE_MEM) +#if !defined(kvm_arch_has_private_mem) && !IS_ENABLED(CONFIG_KVM_GUEST_MEMFD) static inline bool kvm_arch_has_private_mem(struct kvm *kvm) { return false; @@ -2505,7 +2505,7 @@ 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_PRIVATE_MEM) && + return IS_ENABLED(CONFIG_KVM_GUEST_MEMFD) && kvm_get_memory_attributes(kvm, gfn) & KVM_MEMORY_ATTRIBUTE_PRIVATE; } #else @@ -2515,7 +2515,7 @@ static inline bool kvm_mem_is_private(struct kvm *kvm, gfn_t gfn) } #endif /* CONFIG_KVM_GENERIC_MEMORY_ATTRIBUTES */ -#ifdef CONFIG_KVM_PRIVATE_MEM +#ifdef CONFIG_KVM_GUEST_MEMFD int kvm_gmem_get_pfn(struct kvm *kvm, struct kvm_memory_slot *slot, gfn_t gfn, kvm_pfn_t *pfn, struct page **page, int *max_order); @@ -2528,7 +2528,7 @@ static inline int kvm_gmem_get_pfn(struct kvm *kvm, KVM_BUG_ON(1, kvm); return -EIO; } -#endif /* CONFIG_KVM_PRIVATE_MEM */ +#endif /* CONFIG_KVM_GUEST_MEMFD */ #ifdef CONFIG_HAVE_KVM_ARCH_GMEM_PREPARE int kvm_arch_gmem_prepare(struct kvm *kvm, gfn_t gfn, kvm_pfn_t pfn, int max_order); -- cgit v1.2.3 From 36cf63bb5df68836e55e2839f8174b404d47670b Mon Sep 17 00:00:00 2001 From: Fuad Tabba Date: Tue, 29 Jul 2025 15:54:36 -0700 Subject: KVM: Rename CONFIG_KVM_GENERIC_PRIVATE_MEM to CONFIG_HAVE_KVM_ARCH_GMEM_POPULATE The original name was vague regarding its functionality. This Kconfig option specifically enables and gates the kvm_gmem_populate() function, which is responsible for populating a GPA range with guest data. The new name, HAVE_KVM_ARCH_GMEM_POPULATE, describes the purpose of the option: to enable arch-specific guest_memfd population mechanisms. It also follows the same pattern as the other HAVE_KVM_ARCH_* configuration options. This improves clarity for developers and ensures the name accurately reflects the functionality it controls, especially as guest_memfd support expands beyond purely "private" memory scenarios. Temporarily keep KVM_GENERIC_PRIVATE_MEM as an x86-only config so as to minimize churn, and to hopefully make it easier to see what features require HAVE_KVM_ARCH_GMEM_POPULATE. On that note, omit GMEM_POPULATE for KVM_X86_SW_PROTECTED_VM, as regular ol' memset() suffices for software-protected VMs. As for KVM_GENERIC_PRIVATE_MEM, a future change will select KVM_GUEST_MEMFD for all 64-bit KVM builds, at which point the intermediate config will become obsolete and can/will be dropped. Reviewed-by: Ira Weiny Reviewed-by: Gavin Shan Reviewed-by: Shivank Garg Reviewed-by: Vlastimil Babka Co-developed-by: David Hildenbrand Signed-off-by: David Hildenbrand Signed-off-by: Fuad Tabba Reviewed-by: Xiaoyao Li Co-developed-by: Sean Christopherson Signed-off-by: Sean Christopherson Message-ID: <20250729225455.670324-6-seanjc@google.com> Signed-off-by: Paolo Bonzini --- include/linux/kvm_host.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'include/linux/kvm_host.h') diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h index 8cdc0b3cc1b1..ddfb6cfe20a6 100644 --- a/include/linux/kvm_host.h +++ b/include/linux/kvm_host.h @@ -2534,7 +2534,7 @@ static inline int kvm_gmem_get_pfn(struct kvm *kvm, int kvm_arch_gmem_prepare(struct kvm *kvm, gfn_t gfn, kvm_pfn_t pfn, int max_order); #endif -#ifdef CONFIG_KVM_GENERIC_PRIVATE_MEM +#ifdef CONFIG_HAVE_KVM_ARCH_GMEM_POPULATE /** * kvm_gmem_populate() - Populate/prepare a GPA range with guest data * -- cgit v1.2.3 From 923310be23b275f730e8869abc783db6296fc043 Mon Sep 17 00:00:00 2001 From: Fuad Tabba Date: Tue, 29 Jul 2025 15:54:37 -0700 Subject: KVM: Rename kvm_slot_can_be_private() to kvm_slot_has_gmem() Rename kvm_slot_can_be_private() to kvm_slot_has_gmem() to improve clarity and accurately reflect its purpose. The function kvm_slot_can_be_private() was previously used to check if a given kvm_memory_slot is backed by guest_memfd. However, its name implied that the memory in such a slot was exclusively "private". As guest_memfd support expands to include non-private memory (e.g., shared host mappings), it's important to remove this association. The new name, kvm_slot_has_gmem(), states that the slot is backed by guest_memfd without making assumptions about the memory's privacy attributes. Reviewed-by: Ira Weiny Reviewed-by: Gavin Shan Reviewed-by: Shivank Garg Reviewed-by: Vlastimil Babka Reviewed-by: Xiaoyao Li Co-developed-by: David Hildenbrand Signed-off-by: David Hildenbrand Signed-off-by: Fuad Tabba Signed-off-by: Sean Christopherson Message-ID: <20250729225455.670324-7-seanjc@google.com> Signed-off-by: Paolo Bonzini --- include/linux/kvm_host.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'include/linux/kvm_host.h') diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h index ddfb6cfe20a6..4c5e0a898652 100644 --- a/include/linux/kvm_host.h +++ b/include/linux/kvm_host.h @@ -615,7 +615,7 @@ struct kvm_memory_slot { #endif }; -static inline bool kvm_slot_can_be_private(const struct kvm_memory_slot *slot) +static inline bool kvm_slot_has_gmem(const struct kvm_memory_slot *slot) { return slot && (slot->flags & KVM_MEM_GUEST_MEMFD); } -- cgit v1.2.3 From 69116e01f6fee030db45d269f28f9c300b8dc9d6 Mon Sep 17 00:00:00 2001 From: Fuad Tabba Date: Tue, 29 Jul 2025 15:54:38 -0700 Subject: KVM: Fix comments that refer to slots_lock Fix comments so that they refer to slots_lock instead of slots_locks (remove trailing s). Reviewed-by: David Hildenbrand Reviewed-by: Ira Weiny Reviewed-by: Gavin Shan Reviewed-by: Shivank Garg Reviewed-by: Vlastimil Babka Reviewed-by: Xiaoyao Li Signed-off-by: Fuad Tabba Signed-off-by: Sean Christopherson Message-ID: <20250729225455.670324-8-seanjc@google.com> Signed-off-by: Paolo Bonzini --- include/linux/kvm_host.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'include/linux/kvm_host.h') diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h index 4c5e0a898652..5c25b03d3d50 100644 --- a/include/linux/kvm_host.h +++ b/include/linux/kvm_host.h @@ -860,7 +860,7 @@ struct kvm { struct notifier_block pm_notifier; #endif #ifdef CONFIG_KVM_GENERIC_MEMORY_ATTRIBUTES - /* Protected by slots_locks (for writes) and RCU (for reads) */ + /* Protected by slots_lock (for writes) and RCU (for reads) */ struct xarray mem_attr_array; #endif char stats_id[KVM_STATS_NAME_SIZE]; -- cgit v1.2.3 From 68d189938709a5918d7308eb922c30bcbf16ebb9 Mon Sep 17 00:00:00 2001 From: Fuad Tabba Date: Tue, 29 Jul 2025 15:54:39 -0700 Subject: KVM: Fix comment that refers to kvm uapi header path The comment that points to the path where the user-visible memslot flags are refers to an outdated path and has a typo. Update the comment to refer to the correct path. Reviewed-by: David Hildenbrand Reviewed-by: Gavin Shan Reviewed-by: Shivank Garg Reviewed-by: Vlastimil Babka Reviewed-by: Xiaoyao Li Signed-off-by: Fuad Tabba Signed-off-by: Sean Christopherson Message-ID: <20250729225455.670324-9-seanjc@google.com> Signed-off-by: Paolo Bonzini --- include/linux/kvm_host.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'include/linux/kvm_host.h') diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h index 5c25b03d3d50..56ea8c862cfd 100644 --- a/include/linux/kvm_host.h +++ b/include/linux/kvm_host.h @@ -52,7 +52,7 @@ /* * The bit 16 ~ bit 31 of kvm_userspace_memory_region::flags are internally * used in kvm, other bits are visible for userspace which are defined in - * include/linux/kvm_h. + * include/uapi/linux/kvm.h. */ #define KVM_MEMSLOT_INVALID (1UL << 16) -- cgit v1.2.3 From d1e54dd08f163a9021433020d16a8f8f70ddc41c Mon Sep 17 00:00:00 2001 From: Fuad Tabba Date: Tue, 29 Jul 2025 15:54:40 -0700 Subject: KVM: x86: Enable KVM_GUEST_MEMFD for all 64-bit builds 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 Reviewed-by: Xiaoyao Li Reviewed-by: David Hildenbrand Signed-off-by: Sean Christopherson Message-ID: <20250729225455.670324-10-seanjc@google.com> Signed-off-by: Paolo Bonzini --- include/linux/kvm_host.h | 9 ++------- 1 file changed, 2 insertions(+), 7 deletions(-) (limited to 'include/linux/kvm_host.h') 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) -- cgit v1.2.3 From a12578e1477cbfb547256ed8dee6d5142a59cdcd Mon Sep 17 00:00:00 2001 From: Fuad Tabba Date: Tue, 29 Jul 2025 15:54:41 -0700 Subject: KVM: guest_memfd: Add plumbing to host to map guest_memfd pages Introduce the core infrastructure to enable host userspace to mmap() guest_memfd-backed memory. This is needed for several evolving KVM use cases: * Non-CoCo VM backing: Allows VMMs like Firecracker to run guests entirely backed by guest_memfd, even for non-CoCo VMs [1]. This provides a unified memory management model and simplifies guest memory handling. * Direct map removal for enhanced security: This is an important step for direct map removal of guest memory [2]. By allowing host userspace to fault in guest_memfd pages directly, we can avoid maintaining host kernel direct maps of guest memory. This provides additional hardening against Spectre-like transient execution attacks by removing a potential attack surface within the kernel. * Future guest_memfd features: This also lays the groundwork for future enhancements to guest_memfd, such as supporting huge pages and enabling in-place sharing of guest memory with the host for CoCo platforms that permit it [3]. Enable the basic mmap and fault handling logic within guest_memfd, but hold off on allow userspace to actually do mmap() until the architecture support is also in place. [1] https://github.com/firecracker-microvm/firecracker/tree/feature/secret-hiding [2] https://lore.kernel.org/linux-mm/cc1bb8e9bc3e1ab637700a4d3defeec95b55060a.camel@amazon.com [3] https://lore.kernel.org/all/c1c9591d-218a-495c-957b-ba356c8f8e09@redhat.com/T/#u Reviewed-by: Gavin Shan Reviewed-by: Shivank Garg Acked-by: David Hildenbrand Co-developed-by: Ackerley Tng Signed-off-by: Ackerley Tng Signed-off-by: Fuad Tabba Reviewed-by: Xiaoyao Li Signed-off-by: Sean Christopherson Message-ID: <20250729225455.670324-11-seanjc@google.com> Signed-off-by: Paolo Bonzini --- include/linux/kvm_host.h | 4 ++++ 1 file changed, 4 insertions(+) (limited to 'include/linux/kvm_host.h') diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h index 4d1c44622056..26bad600f9fa 100644 --- a/include/linux/kvm_host.h +++ b/include/linux/kvm_host.h @@ -726,6 +726,10 @@ static inline bool kvm_arch_has_private_mem(struct kvm *kvm) } #endif +#ifdef CONFIG_KVM_GUEST_MEMFD +bool kvm_arch_supports_gmem_mmap(struct kvm *kvm); +#endif + #ifndef kvm_arch_has_readonly_mem static inline bool kvm_arch_has_readonly_mem(struct kvm *kvm) { -- cgit v1.2.3 From 576d035e2aef52f8d8d3ce29af556d4c6bd2e0fe Mon Sep 17 00:00:00 2001 From: Fuad Tabba Date: Tue, 29 Jul 2025 15:54:42 -0700 Subject: KVM: guest_memfd: Track guest_memfd mmap support in memslot Add a new internal flag, KVM_MEMSLOT_GMEM_ONLY, to the top half of memslot->flags (which makes it strictly for KVM's internal use). This flag tracks when a guest_memfd-backed memory slot supports host userspace mmap operations, which implies that all memory, not just private memory for CoCo VMs, is consumed through guest_memfd: "gmem only". This optimization avoids repeatedly checking the underlying guest_memfd file for mmap support, which would otherwise require taking and releasing a reference on the file for each check. By caching this information directly in the memslot, we reduce overhead and simplify the logic involved in handling guest_memfd-backed pages for host mappings. Reviewed-by: Gavin Shan Reviewed-by: Shivank Garg Reviewed-by: Xiaoyao Li Acked-by: David Hildenbrand Suggested-by: David Hildenbrand Signed-off-by: Fuad Tabba Signed-off-by: Sean Christopherson Message-ID: <20250729225455.670324-12-seanjc@google.com> Signed-off-by: Paolo Bonzini --- include/linux/kvm_host.h | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-) (limited to 'include/linux/kvm_host.h') diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h index 26bad600f9fa..8b47891adca1 100644 --- a/include/linux/kvm_host.h +++ b/include/linux/kvm_host.h @@ -54,7 +54,8 @@ * used in kvm, other bits are visible for userspace which are defined in * include/uapi/linux/kvm.h. */ -#define KVM_MEMSLOT_INVALID (1UL << 16) +#define KVM_MEMSLOT_INVALID (1UL << 16) +#define KVM_MEMSLOT_GMEM_ONLY (1UL << 17) /* * Bit 63 of the memslot generation number is an "update in-progress flag", @@ -2490,6 +2491,14 @@ static inline void kvm_prepare_memory_fault_exit(struct kvm_vcpu *vcpu, vcpu->run->memory_fault.flags |= KVM_MEMORY_EXIT_FLAG_PRIVATE; } +static inline bool kvm_memslot_is_gmem_only(const struct kvm_memory_slot *slot) +{ + if (!IS_ENABLED(CONFIG_KVM_GUEST_MEMFD)) + return false; + + return slot->flags & KVM_MEMSLOT_GMEM_ONLY; +} + #ifdef CONFIG_KVM_GENERIC_MEMORY_ATTRIBUTES static inline unsigned long kvm_get_memory_attributes(struct kvm *kvm, gfn_t gfn) { -- cgit v1.2.3 From 7788255aba6545a27b8d143c5256536f8dfb2c0a Mon Sep 17 00:00:00 2001 From: Keir Fraser Date: Tue, 9 Sep 2025 10:00:06 +0000 Subject: KVM: Implement barriers before accessing kvm->buses[] on SRCU read paths This ensures that, if a VCPU has "observed" that an IO registration has occurred, the instruction currently being trapped or emulated will also observe the IO registration. At the same time, enforce that kvm_get_bus() is used only on the update side, ensuring that a long-term reference cannot be obtained by an SRCU reader. Signed-off-by: Keir Fraser Signed-off-by: Marc Zyngier --- include/linux/kvm_host.h | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-) (limited to 'include/linux/kvm_host.h') diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h index 15656b7fba6c..e7d6111cf254 100644 --- a/include/linux/kvm_host.h +++ b/include/linux/kvm_host.h @@ -966,11 +966,15 @@ static inline bool kvm_dirty_log_manual_protect_and_init_set(struct kvm *kvm) return !!(kvm->manual_dirty_log_protect & KVM_DIRTY_LOG_INITIALLY_SET); } +/* + * Get a bus reference under the update-side lock. No long-term SRCU reader + * references are permitted, to avoid stale reads vs concurrent IO + * registrations. + */ static inline struct kvm_io_bus *kvm_get_bus(struct kvm *kvm, enum kvm_bus idx) { - return srcu_dereference_check(kvm->buses[idx], &kvm->srcu, - lockdep_is_held(&kvm->slots_lock) || - !refcount_read(&kvm->users_count)); + return rcu_dereference_protected(kvm->buses[idx], + lockdep_is_held(&kvm->slots_lock)); } static inline struct kvm_vcpu *kvm_get_vcpu(struct kvm *kvm, int i) -- cgit v1.2.3 From 7d9a0273c45962e9a6bc06f3b87eef7c431c1853 Mon Sep 17 00:00:00 2001 From: Keir Fraser Date: Tue, 9 Sep 2025 10:00:07 +0000 Subject: KVM: Avoid synchronize_srcu() in kvm_io_bus_register_dev() Device MMIO registration may happen quite frequently during VM boot, and the SRCU synchronization each time has a measurable effect on VM startup time. In our experiments it can account for around 25% of a VM's startup time. Replace the synchronization with a deferred free of the old kvm_io_bus structure. Tested-by: Li RongQing Signed-off-by: Keir Fraser Signed-off-by: Marc Zyngier --- include/linux/kvm_host.h | 1 + 1 file changed, 1 insertion(+) (limited to 'include/linux/kvm_host.h') diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h index e7d6111cf254..103be35caf0d 100644 --- a/include/linux/kvm_host.h +++ b/include/linux/kvm_host.h @@ -206,6 +206,7 @@ struct kvm_io_range { struct kvm_io_bus { int dev_count; int ioeventfd_count; + struct rcu_head rcu; struct kvm_io_range range[]; }; -- cgit v1.2.3 From 6d0386ea99875313fdfd074eb74013b6e3b48a76 Mon Sep 17 00:00:00 2001 From: Sean Christopherson Date: Wed, 27 Aug 2025 17:01:53 -0700 Subject: entry/kvm: KVM: Move KVM details related to signal/-EINTR into KVM proper Move KVM's morphing of pending signals into userspace exits into KVM proper, and drop the @vcpu param from xfer_to_guest_mode_handle_work(). How KVM responds to -EINTR is a detail that really belongs in KVM itself, and invoking kvm_handle_signal_exit() from kernel code creates an inverted module dependency. E.g. attempting to move kvm_handle_signal_exit() into kvm_main.c would generate an linker error when building kvm.ko as a module. Dropping KVM details will also converting the KVM "entry" code into a more generic virtualization framework so that it can be used when running as a Hyper-V root partition. Lastly, eliminating usage of "struct kvm_vcpu" outside of KVM is also nice to have for KVM x86 developers, as keeping the details of kvm_vcpu purely within KVM allows changing the layout of the structure without having to boot into a new kernel, e.g. allows rebuilding and reloading kvm.ko with a modified kvm_vcpu structure as part of debug/development. Signed-off-by: Sean Christopherson Reviewed-by: Thomas Gleixner Signed-off-by: Wei Liu --- include/linux/kvm_host.h | 13 ++++++++++++- 1 file changed, 12 insertions(+), 1 deletion(-) (limited to 'include/linux/kvm_host.h') diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h index 15656b7fba6c..598b9473e46d 100644 --- a/include/linux/kvm_host.h +++ b/include/linux/kvm_host.h @@ -2,7 +2,7 @@ #ifndef __KVM_HOST_H #define __KVM_HOST_H - +#include #include #include #include @@ -2450,6 +2450,17 @@ static inline void kvm_handle_signal_exit(struct kvm_vcpu *vcpu) vcpu->run->exit_reason = KVM_EXIT_INTR; vcpu->stat.signal_exits++; } + +static inline int kvm_xfer_to_guest_mode_handle_work(struct kvm_vcpu *vcpu) +{ + int r = xfer_to_guest_mode_handle_work(); + + if (r) { + WARN_ON_ONCE(r != -EINTR); + kvm_handle_signal_exit(vcpu); + } + return r; +} #endif /* CONFIG_KVM_XFER_TO_GUEST_WORK */ /* -- cgit v1.2.3 From 9be7e1e320ff2e7db4b23c8ec5f599bbfac94ede Mon Sep 17 00:00:00 2001 From: Sean Christopherson Date: Wed, 27 Aug 2025 17:01:54 -0700 Subject: entry: Rename "kvm" entry code assets to "virt" to genericize APIs Rename the "kvm" entry code files and Kconfigs to use generic "virt" nomenclature so that the code can be reused by other hypervisors (or rather, their root/dom0 partition drivers), without incorrectly suggesting the code somehow relies on and/or involves KVM. No functional change intended. Signed-off-by: Sean Christopherson Reviewed-by: Thomas Gleixner Reviewed-by: Joel Fernandes Signed-off-by: Wei Liu --- include/linux/kvm_host.h | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) (limited to 'include/linux/kvm_host.h') diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h index 598b9473e46d..70ac2267d5d0 100644 --- a/include/linux/kvm_host.h +++ b/include/linux/kvm_host.h @@ -2,7 +2,7 @@ #ifndef __KVM_HOST_H #define __KVM_HOST_H -#include +#include #include #include #include @@ -2444,7 +2444,7 @@ static inline int kvm_arch_vcpu_run_pid_change(struct kvm_vcpu *vcpu) } #endif /* CONFIG_HAVE_KVM_VCPU_RUN_PID_CHANGE */ -#ifdef CONFIG_KVM_XFER_TO_GUEST_WORK +#ifdef CONFIG_VIRT_XFER_TO_GUEST_WORK static inline void kvm_handle_signal_exit(struct kvm_vcpu *vcpu) { vcpu->run->exit_reason = KVM_EXIT_INTR; @@ -2461,7 +2461,7 @@ static inline int kvm_xfer_to_guest_mode_handle_work(struct kvm_vcpu *vcpu) } return r; } -#endif /* CONFIG_KVM_XFER_TO_GUEST_WORK */ +#endif /* CONFIG_VIRT_XFER_TO_GUEST_WORK */ /* * If more than one page is being (un)accounted, @virt must be the address of -- cgit v1.2.3 From 44c6cb9fe9888b371e31165b2854bd0f4e2787d4 Mon Sep 17 00:00:00 2001 From: Sean Christopherson Date: Fri, 3 Oct 2025 16:25:58 -0700 Subject: KVM: guest_memfd: Allow mmap() on guest_memfd for x86 VMs with private memory Allow mmap() on guest_memfd instances for x86 VMs with private memory as the need to track private vs. shared state in the guest_memfd instance is only pertinent to INIT_SHARED. Doing mmap() on private memory isn't terrible useful (yet!), but it's now possible, and will be desirable when guest_memfd gains support for other VMA-based syscalls, e.g. mbind() to set NUMA policy. Lift the restriction now, before MMAP support is officially released, so that KVM doesn't need to add another capability to enumerate support for mmap() on private memory. Fixes: 3d3a04fad25a ("KVM: Allow and advertise support for host mmap() on guest_memfd files") Reviewed-by: Ackerley Tng Tested-by: Ackerley Tng Reviewed-by: David Hildenbrand Link: https://lore.kernel.org/r/20251003232606.4070510-6-seanjc@google.com Signed-off-by: Sean Christopherson --- include/linux/kvm_host.h | 12 +++++++++++- 1 file changed, 11 insertions(+), 1 deletion(-) (limited to 'include/linux/kvm_host.h') diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h index 19b8c4bebb9c..680ca838f018 100644 --- a/include/linux/kvm_host.h +++ b/include/linux/kvm_host.h @@ -729,7 +729,17 @@ static inline bool kvm_arch_has_private_mem(struct kvm *kvm) #endif #ifdef CONFIG_KVM_GUEST_MEMFD -bool kvm_arch_supports_gmem_mmap(struct kvm *kvm); +bool kvm_arch_supports_gmem_init_shared(struct kvm *kvm); + +static inline u64 kvm_gmem_get_supported_flags(struct kvm *kvm) +{ + u64 flags = GUEST_MEMFD_FLAG_MMAP; + + if (!kvm || kvm_arch_supports_gmem_init_shared(kvm)) + flags |= GUEST_MEMFD_FLAG_INIT_SHARED; + + return flags; +} #endif #ifndef kvm_arch_has_readonly_mem -- cgit v1.2.3