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Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm

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Pull x86 kvm fixes from Paolo Bonzini:
 "x86 fixes.  Everyone else is already in holiday mood apparently.

   - Add a missing 'break' to fix param parsing in the rseq selftest

   - Apply runtime updates to the _current_ CPUID when userspace is
     setting CPUID, e.g. as part of vCPU hotplug, to fix a false
     positive and to avoid dropping the pending update

   - Disallow toggling KVM_MEM_GUEST_MEMFD on an existing memslot, as
     it's not supported by KVM and leads to a use-after-free due to KVM
     failing to unbind the memslot from the previously-associated
     guest_memfd instance

   - Harden against similar KVM_MEM_GUEST_MEMFD goofs, and prepare for
     supporting flags-only changes on KVM_MEM_GUEST_MEMFD memlslots,
     e.g. for dirty logging

   - Set exit_code[63:32] to -1 (all 0xffs) when synthesizing a nested
     SVM_EXIT_ERR (a.k.a. VMEXIT_INVALID) #VMEXIT, as VMEXIT_INVALID is
     defined as -1ull (a 64-bit value)

   - Update SVI when activating APICv to fix a bug where a
     post-activation EOI for an in-service IRQ would effective be lost
     due to SVI being stale

   - Immediately refresh APICv controls (if necessary) on a nested
     VM-Exit instead of deferring the update via KVM_REQ_APICV_UPDATE,
     as the request is effectively ignored because KVM thinks the vCPU
     already has the correct APICv settings"

* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm:
  KVM: nVMX: Immediately refresh APICv controls as needed on nested VM-Exit
  KVM: VMX: Update SVI during runtime APICv activation
  KVM: nSVM: Set exit_code_hi to -1 when synthesizing SVM_EXIT_ERR (failed VMRUN)
  KVM: nSVM: Clear exit_code_hi in VMCB when synthesizing nested VM-Exits
  KVM: Harden and prepare for modifying existing guest_memfd memslots
  KVM: Disallow toggling KVM_MEM_GUEST_MEMFD on an existing memslot
  KVM: selftests: Add a CPUID testcase for KVM_SET_CPUID2 with runtime updates
  KVM: x86: Apply runtime updates to current CPUID during KVM_SET_CPUID{,2}
  KVM: selftests: Add missing "break" in rseq_test's param parsing
This commit is contained in:
Linus Torvalds
2025-12-20 11:31:37 -08:00
parent 255a918a94 0499add8ef
commit 072c0b4f0f
10 changed files with 58 additions and 18 deletions
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1
tools/testing/selftests/kvm/rseq_test.c
View File

@@ -215,6 +215,7 @@ int main(int argc, char *argv[])
switch (opt) {
case 'u':
skip_sanity_check = true;
break;
case 'l':
latency = atoi_paranoid(optarg);
break;

15
tools/testing/selftests/kvm/x86/cpuid_test.c
View File

@@ -155,6 +155,7 @@ struct kvm_cpuid2 *vcpu_alloc_cpuid(struct kvm_vm *vm, vm_vaddr_t *p_gva, struct
static void set_cpuid_after_run(struct kvm_vcpu *vcpu)
{
struct kvm_cpuid_entry2 *ent;
struct kvm_sregs sregs;
int rc;
u32 eax, ebx, x;
@@ -162,6 +163,20 @@ static void set_cpuid_after_run(struct kvm_vcpu *vcpu)
rc = __vcpu_set_cpuid(vcpu);
TEST_ASSERT(!rc, "Setting unmodified CPUID after KVM_RUN failed: %d", rc);
/*
* Toggle CR4 bits that affect dynamic CPUID feature flags to verify
* setting unmodified CPUID succeeds with runtime CPUID updates.
*/
vcpu_sregs_get(vcpu, &sregs);
if (kvm_cpu_has(X86_FEATURE_XSAVE))
sregs.cr4 ^= X86_CR4_OSXSAVE;
if (kvm_cpu_has(X86_FEATURE_PKU))
sregs.cr4 ^= X86_CR4_PKE;
vcpu_sregs_set(vcpu, &sregs);
rc = __vcpu_set_cpuid(vcpu);
TEST_ASSERT(!rc, "Setting unmodified CPUID after KVM_RUN failed: %d", rc);
/* Changing CPU features is forbidden */
ent = vcpu_get_cpuid_entry(vcpu, 0x7);
ebx = ent->ebx;