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

Pull kvm fixes from Paolo Bonzini:
 "While last week's pull request contained miscellaneous fixes for x86,
  this one covers other architectures, selftests changes, and a bigger
  series for APIC virtualization bugs that were discovered during 5.20
  development. The idea is to base 5.20 development for KVM on top of
  this tag.

  ARM64:

   - Properly reset the SVE/SME flags on vcpu load

   - Fix a vgic-v2 regression regarding accessing the pending state of a
     HW interrupt from userspace (and make the code common with vgic-v3)

   - Fix access to the idreg range for protected guests

   - Ignore 'kvm-arm.mode=protected' when using VHE

   - Return an error from kvm_arch_init_vm() on allocation failure

   - A bunch of small cleanups (comments, annotations, indentation)

  RISC-V:

   - Typo fix in arch/riscv/kvm/vmid.c

   - Remove broken reference pattern from MAINTAINERS entry

  x86-64:

   - Fix error in page tables with MKTME enabled

   - Dirty page tracking performance test extended to running a nested
     guest

   - Disable APICv/AVIC in cases that it cannot implement correctly"

[ This merge also fixes a misplaced end parenthesis bug introduced in
  commit 3743c2f02517 ("KVM: x86: inhibit APICv/AVIC on changes to APIC
  ID or APIC base") pointed out by Sean Christopherson ]

Link: https://lore.kernel.org/all/20220610191813.371682-1-seanjc@google.com/

* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (34 commits)
  KVM: selftests: Restrict test region to 48-bit physical addresses when using nested
  KVM: selftests: Add option to run dirty_log_perf_test vCPUs in L2
  KVM: selftests: Clean up LIBKVM files in Makefile
  KVM: selftests: Link selftests directly with lib object files
  KVM: selftests: Drop unnecessary rule for STATIC_LIBS
  KVM: selftests: Add a helper to check EPT/VPID capabilities
  KVM: selftests: Move VMX_EPT_VPID_CAP_AD_BITS to vmx.h
  KVM: selftests: Refactor nested_map() to specify target level
  KVM: selftests: Drop stale function parameter comment for nested_map()
  KVM: selftests: Add option to create 2M and 1G EPT mappings
  KVM: selftests: Replace x86_page_size with PG_LEVEL_XX
  KVM: x86: SVM: fix nested PAUSE filtering when L0 intercepts PAUSE
  KVM: x86: SVM: drop preempt-safe wrappers for avic_vcpu_load/put
  KVM: x86: disable preemption around the call to kvm_arch_vcpu_{un|}blocking
  KVM: x86: disable preemption while updating apicv inhibition
  KVM: x86: SVM: fix avic_kick_target_vcpus_fast
  KVM: x86: SVM: remove avic's broken code that updated APIC ID
  KVM: x86: inhibit APICv/AVIC on changes to APIC ID or APIC base
  KVM: x86: document AVIC/APICv inhibit reasons
  KVM: x86/mmu: Set memory encryption "value", not "mask", in shadow PDPTRs
  ...

1 files changed, 65 insertions, 2 deletions

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 3a240a64ac68..9217bd6cf0d1 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -1047,14 +1047,77 @@ struct kvm_x86_msr_filter {
 };
 
 enum kvm_apicv_inhibit {
+
+	/********************************************************************/
+	/* INHIBITs that are relevant to both Intel's APICv and AMD's AVIC. */
+	/********************************************************************/
+
+	/*
+	 * APIC acceleration is disabled by a module parameter
+	 * and/or not supported in hardware.
+	 */
 	APICV_INHIBIT_REASON_DISABLE,
+
+	/*
+	 * APIC acceleration is inhibited because AutoEOI feature is
+	 * being used by a HyperV guest.
+	 */
 	APICV_INHIBIT_REASON_HYPERV,
+
+	/*
+	 * APIC acceleration is inhibited because the userspace didn't yet
+	 * enable the kernel/split irqchip.
+	 */
+	APICV_INHIBIT_REASON_ABSENT,
+
+	/* APIC acceleration is inhibited because KVM_GUESTDBG_BLOCKIRQ
+	 * (out of band, debug measure of blocking all interrupts on this vCPU)
+	 * was enabled, to avoid AVIC/APICv bypassing it.
+	 */
+	APICV_INHIBIT_REASON_BLOCKIRQ,
+
+	/*
+	 * For simplicity, the APIC acceleration is inhibited
+	 * first time either APIC ID or APIC base are changed by the guest
+	 * from their reset values.
+	 */
+	APICV_INHIBIT_REASON_APIC_ID_MODIFIED,
+	APICV_INHIBIT_REASON_APIC_BASE_MODIFIED,
+
+	/******************************************************/
+	/* INHIBITs that are relevant only to the AMD's AVIC. */
+	/******************************************************/
+
+	/*
+	 * AVIC is inhibited on a vCPU because it runs a nested guest.
+	 *
+	 * This is needed because unlike APICv, the peers of this vCPU
+	 * cannot use the doorbell mechanism to signal interrupts via AVIC when
+	 * a vCPU runs nested.
+	 */
 	APICV_INHIBIT_REASON_NESTED,
+
+	/*
+	 * On SVM, the wait for the IRQ window is implemented with pending vIRQ,
+	 * which cannot be injected when the AVIC is enabled, thus AVIC
+	 * is inhibited while KVM waits for IRQ window.
+	 */
 	APICV_INHIBIT_REASON_IRQWIN,
+
+	/*
+	 * PIT (i8254) 're-inject' mode, relies on EOI intercept,
+	 * which AVIC doesn't support for edge triggered interrupts.
+	 */
 	APICV_INHIBIT_REASON_PIT_REINJ,
+
+	/*
+	 * AVIC is inhibited because the guest has x2apic in its CPUID.
+	 */
 	APICV_INHIBIT_REASON_X2APIC,
-	APICV_INHIBIT_REASON_BLOCKIRQ,
-	APICV_INHIBIT_REASON_ABSENT,
+
+	/*
+	 * AVIC is disabled because SEV doesn't support it.
+	 */
 	APICV_INHIBIT_REASON_SEV,
 };