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

Pull kvm fixes from Paolo Bonzini:
 "s390:

   - Fix failure to start guests with kvm.use_gisa=0

   - Panic if (un)share fails to maintain security.

  ARM:

   - Use kvfree() for the kvmalloc'd nested MMUs array

   - Set of fixes to address warnings in W=1 builds

   - Make KVM depend on assembler support for ARMv8.4

   - Fix for vgic-debug interface for VMs without LPIs

   - Actually check ID_AA64MMFR3_EL1.S1PIE in get-reg-list selftest

   - Minor code / comment cleanups for configuring PAuth traps

   - Take kvm->arch.config_lock to prevent destruction / initialization
     race for a vCPU's CPUIF which may lead to a UAF

  x86:

   - Disallow read-only memslots for SEV-ES and SEV-SNP (and TDX)

   - Fix smatch issues

   - Small cleanups

   - Make x2APIC ID 100% readonly

   - Fix typo in uapi constant

  Generic:

   - Use synchronize_srcu_expedited() on irqfd shutdown"

* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (21 commits)
  KVM: SEV: uapi: fix typo in SEV_RET_INVALID_CONFIG
  KVM: x86: Disallow read-only memslots for SEV-ES and SEV-SNP (and TDX)
  KVM: eventfd: Use synchronize_srcu_expedited() on shutdown
  KVM: selftests: Add a testcase to verify x2APIC is fully readonly
  KVM: x86: Make x2APIC ID 100% readonly
  KVM: x86: Use this_cpu_ptr() instead of per_cpu_ptr(smp_processor_id())
  KVM: x86: hyper-v: Remove unused inline function kvm_hv_free_pa_page()
  KVM: SVM: Fix an error code in sev_gmem_post_populate()
  KVM: SVM: Fix uninitialized variable bug
  KVM: arm64: vgic: Hold config_lock while tearing down a CPU interface
  KVM: selftests: arm64: Correct feature test for S1PIE in get-reg-list
  KVM: arm64: Tidying up PAuth code in KVM
  KVM: arm64: vgic-debug: Exit the iterator properly w/o LPI
  KVM: arm64: Enforce dependency on an ARMv8.4-aware toolchain
  s390/uv: Panic for set and remove shared access UVC errors
  KVM: s390: fix validity interception issue when gisa is switched off
  docs: KVM: Fix register ID of SPSR_FIQ
  KVM: arm64: vgic: fix unexpected unlock sparse warnings
  KVM: arm64: fix kdoc warnings in W=1 builds
  KVM: arm64: fix override-init warnings in W=1 builds
  ...

1 files changed, 15 insertions, 7 deletions

diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c
index 4915acdbfcd8..5bb481aefcbc 100644
--- a/arch/x86/kvm/lapic.c
+++ b/arch/x86/kvm/lapic.c
@@ -351,10 +351,8 @@ static void kvm_recalculate_logical_map(struct kvm_apic_map *new,
 	 * reversing the LDR calculation to get cluster of APICs, i.e. no
 	 * additional work is required.
 	 */
-	if (apic_x2apic_mode(apic)) {
-		WARN_ON_ONCE(ldr != kvm_apic_calc_x2apic_ldr(kvm_x2apic_id(apic)));
+	if (apic_x2apic_mode(apic))
 		return;
-	}
 
 	if (WARN_ON_ONCE(!kvm_apic_map_get_logical_dest(new, ldr,
 							&cluster, &mask))) {
@@ -2966,18 +2964,28 @@ static int kvm_apic_state_fixup(struct kvm_vcpu *vcpu,
 		struct kvm_lapic_state *s, bool set)
 {
 	if (apic_x2apic_mode(vcpu->arch.apic)) {
+		u32 x2apic_id = kvm_x2apic_id(vcpu->arch.apic);
 		u32 *id = (u32 *)(s->regs + APIC_ID);
 		u32 *ldr = (u32 *)(s->regs + APIC_LDR);
 		u64 icr;
 
 		if (vcpu->kvm->arch.x2apic_format) {
-			if (*id != vcpu->vcpu_id)
+			if (*id != x2apic_id)
 				return -EINVAL;
 		} else {
+			/*
+			 * Ignore the userspace value when setting APIC state.
+			 * KVM's model is that the x2APIC ID is readonly, e.g.
+			 * KVM only supports delivering interrupts to KVM's
+			 * version of the x2APIC ID.  However, for backwards
+			 * compatibility, don't reject attempts to set a
+			 * mismatched ID for userspace that hasn't opted into
+			 * x2apic_format.
+			 */
 			if (set)
-				*id >>= 24;
+				*id = x2apic_id;
 			else
-				*id <<= 24;
+				*id = x2apic_id << 24;
 		}
 
 		/*
@@ -2986,7 +2994,7 @@ static int kvm_apic_state_fixup(struct kvm_vcpu *vcpu,
 		 * split to ICR+ICR2 in userspace for backwards compatibility.
 		 */
 		if (set) {
-			*ldr = kvm_apic_calc_x2apic_ldr(*id);
+			*ldr = kvm_apic_calc_x2apic_ldr(x2apic_id);
 
 			icr = __kvm_lapic_get_reg(s->regs, APIC_ICR) |
 			      (u64)__kvm_lapic_get_reg(s->regs, APIC_ICR2) << 32;