kernel/git/stable/linux.git/arch/loongarch/kvm/vm.c, branch master

LoongArch: KVM: Fix TOCTOU race on pv_features

2026-09-04T13:45:13+00:00

In kvm_loongarch_cpucfg_set_attr() the check-then-set on kvm->arch.pv_features is lockless, so two vCPUs can race past the validation and set different values. Add a spinlock to protect it. Cc: stable@vger.kernel.org Reviewed-by: Bibo Mao Signed-off-by: Tao Cui Signed-off-by: Huacai Chen

LoongArch: KVM: Advertise already-supported capabilities

2026-08-10T04:21:50+00:00

Several LoongArch KVM features are fully implemented but were never reported through their standard KVM_CHECK_EXTENSION probes, so userspace cannot discover them. Advertise the ones that already work so as to have a real consumer: - KVM_CAP_VCPU_ATTRIBUTES: per-vCPU device-attribute ioctls are implemented (CPUCFG, PVTIME control); advertise the discovery cap. - KVM_CAP_STEAL_TIME: steal time works end-to-end (host-side record plus guest-side paravirt), the probe returns kvm_pvtime_supported(). This doesn't add new functionalities; it only makes existing features discoverable via the standard probe. Reviewed-by: Bibo Mao Signed-off-by: Tao Cui Signed-off-by: Huacai Chen

LoongArch: KVM: Cap KVM_CAP_NR_VCPUS by KVM_CAP_MAX_VCPUS

2026-05-04T01:00:37+00:00

It doesn't make sense to return the recommended maximum number of vCPUs which exceeds the maximum possible number of vCPUs. Other architectures have already done this, such as commit 57a2e13ebdda ("KVM: MIPS: Cap KVM_CAP_NR_VCPUS by KVM_CAP_MAX_VCPUS") Cc: stable@vger.kernel.org Reviewed-by: Bibo Mao Signed-off-by: Qiang Ma Signed-off-by: Huacai Chen

LoongArch: KVM: Fix typo issue in kvm_vm_init_features()

2026-03-16T02:36:02+00:00

Most of VM feature detections are integer OR operations, and integer assignment operation will clear previous integer OR operation. So here change all integer assignment operations to integer OR operations. Fixes: 82db90bf461b ("LoongArch: KVM: Move feature detection in kvm_vm_init_features()") Signed-off-by: Bibo Mao Signed-off-by: Huacai Chen

Merge tag 'kvm-x86-generic-7.0-rc3' of https://github.com/kvm-x86/linux into HEAD

2026-03-11T17:01:55+00:00

KVM generic changes for 7.0 - Remove a subtle pseudo-overlay of kvm_stats_desc, which, aside from being unnecessary and confusing, triggered compiler warnings due to -Wflex-array-member-not-at-end. - Document that vcpu->mutex is take outside of kvm->slots_lock and kvm->slots_arch_lock, which is intentional and desirable despite being rather unintuitive.

KVM: always define KVM_CAP_SYNC_MMU

2026-02-28T14:31:35+00:00

KVM_CAP_SYNC_MMU is provided by KVM's MMU notifiers, which are now always available. Move the definition from individual architectures to common code. Signed-off-by: Paolo Bonzini

treewide: Replace kmalloc with kmalloc_obj for non-scalar types

2026-02-21T09:02:28+00:00

This is the result of running the Coccinelle script from scripts/coccinelle/api/kmalloc_objs.cocci. The script is designed to avoid scalar types (which need careful case-by-case checking), and instead replace kmalloc-family calls that allocate struct or union object instances: Single allocations: kmalloc(sizeof(TYPE), ...) are replaced with: kmalloc_obj(TYPE, ...) Array allocations: kmalloc_array(COUNT, sizeof(TYPE), ...) are replaced with: kmalloc_objs(TYPE, COUNT, ...) Flex array allocations: kmalloc(struct_size(PTR, FAM, COUNT), ...) are replaced with: kmalloc_flex(*PTR, FAM, COUNT, ...) (where TYPE may also be *VAR) The resulting allocations no longer return "void *", instead returning "TYPE *". Signed-off-by: Kees Cook

LoongArch: KVM: Add paravirt preempt feature in hypervisor side

2026-02-06T01:28:01+00:00

Feature KVM_FEATURE_PREEMPT is added to show whether vCPU is preempted or not. It is to help guest OS scheduling or lock checking etc. Here add KVM_FEATURE_PREEMPT feature and use one byte as preempted flag in the steal time structure. Signed-off-by: Bibo Mao Signed-off-by: Huacai Chen

LoongArch: KVM: Move feature detection in kvm_vm_init_features()

2026-02-06T01:27:46+00:00

VM feature detection is sparsed in function kvm_vm_init_features() and kvm_vm_feature_has_attr(). Here move all the features detection in function kvm_vm_init_features(), and there is only feature checking in function kvm_vm_feature_has_attr(). Signed-off-by: Bibo Mao Signed-off-by: Huacai Chen

KVM: Remove subtle "struct kvm_stats_desc" pseudo-overlay

2026-01-08T18:40:48+00:00

Remove KVM's internal pseudo-overlay of kvm_stats_desc, which subtly aliases the flexible name[] in the uAPI definition with a fixed-size array of the same name. The unusual embedded structure results in compiler warnings due to -Wflex-array-member-not-at-end, and also necessitates an extra level of dereferencing in KVM. To avoid the "overlay", define the uAPI structure to have a fixed-size name when building for the kernel. Opportunistically clean up the indentation for the stats macros, and replace spaces with tabs. No functional change intended. Reported-by: Gustavo A. R. Silva Closes: https://lore.kernel.org/all/aPfNKRpLfhmhYqfP@kspp Acked-by: Marc Zyngier Acked-by: Christian Borntraeger [..] Acked-by: Anup Patel Reviewed-by: Bibo Mao Acked-by: Gustavo A. R. Silva Link: https://patch.msgid.link/20251205232655.445294-1-seanjc@google.com Signed-off-by: Sean Christopherson