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

Pull kvm fixes from Paolo Bonzini:
 "More x86 fixes:

   - Logic bugs in CR0 writes and Hyper-V hypercalls

   - Don't use Enlightened MSR Bitmap for L3

   - Remove user-triggerable WARN

  Plus a few selftest fixes and a regression test for the
  user-triggerable WARN"

* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm:
  selftests: KVM: Add test to verify KVM doesn't explode on "bad" I/O
  KVM: x86: Don't WARN if userspace mucks with RCX during string I/O exit
  KVM: X86: Raise #GP when clearing CR0_PG in 64 bit mode
  selftests: KVM: avoid failures due to reserved HyperTransport region
  KVM: x86: Ignore sparse banks size for an "all CPUs", non-sparse IPI req
  KVM: x86: Wait for IPIs to be delivered when handling Hyper-V TLB flush hypercall
  KVM: x86: selftests: svm_int_ctl_test: fix intercept calculation
  KVM: nVMX: Don't use Enlightened MSR Bitmap for L3

1 files changed, 9 insertions, 3 deletions

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index e0aa4dd53c7f..0cf1082455df 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -890,7 +890,8 @@ int kvm_set_cr0(struct kvm_vcpu *vcpu, unsigned long cr0)
 	    !load_pdptrs(vcpu, vcpu->arch.walk_mmu, kvm_read_cr3(vcpu)))
 		return 1;
 
-	if (!(cr0 & X86_CR0_PG) && kvm_read_cr4_bits(vcpu, X86_CR4_PCIDE))
+	if (!(cr0 & X86_CR0_PG) &&
+	    (is_64_bit_mode(vcpu) || kvm_read_cr4_bits(vcpu, X86_CR4_PCIDE)))
 		return 1;
 
 	static_call(kvm_x86_set_cr0)(vcpu, cr0);
@@ -7121,7 +7122,13 @@ static int emulator_pio_in(struct kvm_vcpu *vcpu, int size,
 			   unsigned short port, void *val, unsigned int count)
 {
 	if (vcpu->arch.pio.count) {
-		/* Complete previous iteration.  */
+		/*
+		 * Complete a previous iteration that required userspace I/O.
+		 * Note, @count isn't guaranteed to match pio.count as userspace
+		 * can modify ECX before rerunning the vCPU.  Ignore any such
+		 * shenanigans as KVM doesn't support modifying the rep count,
+		 * and the emulator ensures @count doesn't overflow the buffer.
+		 */
 	} else {
 		int r = __emulator_pio_in(vcpu, size, port, count);
 		if (!r)
@@ -7130,7 +7137,6 @@ static int emulator_pio_in(struct kvm_vcpu *vcpu, int size,
 		/* Results already available, fall through.  */
 	}
 
-	WARN_ON(count != vcpu->arch.pio.count);
 	complete_emulator_pio_in(vcpu, val);
 	return 1;
 }