#include <stdlib.h>
#include <string.h>
#include <sys/ioctl.h>
+#include <pthread.h>
#include "test_util.h"
#include "kvm_util.h"
#define TEST_SYNC_FIELDS (KVM_SYNC_X86_REGS|KVM_SYNC_X86_SREGS|KVM_SYNC_X86_EVENTS)
#define INVALID_SYNC_FIELD 0x80000000
+/*
+ * Toggle CR4.PAE while KVM is processing SREGS, EFER.LME=1 with CR4.PAE=0 is
+ * illegal, and KVM's MMU heavily relies on vCPU state being valid.
+ */
+static noinline void *race_sregs_cr4(void *arg)
+{
+ struct kvm_run *run = (struct kvm_run *)arg;
+ __u64 *cr4 = &run->s.regs.sregs.cr4;
+ __u64 pae_enabled = *cr4;
+ __u64 pae_disabled = *cr4 & ~X86_CR4_PAE;
+
+ for (;;) {
+ WRITE_ONCE(run->kvm_dirty_regs, KVM_SYNC_X86_SREGS);
+ WRITE_ONCE(*cr4, pae_enabled);
+ asm volatile(".rept 512\n\t"
+ "nop\n\t"
+ ".endr");
+ WRITE_ONCE(*cr4, pae_disabled);
+
+ pthread_testcancel();
+ }
+
+ return NULL;
+}
+
+static void race_sync_regs(void *racer)
+{
+ const time_t TIMEOUT = 2; /* seconds, roughly */
+ struct kvm_translation tr;
+ struct kvm_vcpu *vcpu;
+ struct kvm_run *run;
+ struct kvm_vm *vm;
+ pthread_t thread;
+ time_t t;
+
+ vm = vm_create_with_one_vcpu(&vcpu, guest_code);
+ run = vcpu->run;
+
+ run->kvm_valid_regs = KVM_SYNC_X86_SREGS;
+ vcpu_run(vcpu);
+ run->kvm_valid_regs = 0;
+
+ /*
+ * Selftests run 64-bit guests by default, both EFER.LME and CR4.PAE
+ * should already be set in guest state.
+ */
+ TEST_ASSERT((run->s.regs.sregs.cr4 & X86_CR4_PAE) &&
+ (run->s.regs.sregs.efer & EFER_LME),
+ "vCPU should be in long mode, CR4.PAE=%d, EFER.LME=%d",
+ !!(run->s.regs.sregs.cr4 & X86_CR4_PAE),
+ !!(run->s.regs.sregs.efer & EFER_LME));
+
+ ASSERT_EQ(pthread_create(&thread, NULL, racer, (void *)run), 0);
+
+ for (t = time(NULL) + TIMEOUT; time(NULL) < t;) {
+ __vcpu_run(vcpu);
+
+ if (racer == race_sregs_cr4) {
+ tr = (struct kvm_translation) { .linear_address = 0 };
+ __vcpu_ioctl(vcpu, KVM_TRANSLATE, &tr);
+ }
+ }
+
+ ASSERT_EQ(pthread_cancel(thread), 0);
+ ASSERT_EQ(pthread_join(thread, NULL), 0);
+
+ kvm_vm_free(vm);
+}
+
int main(int argc, char *argv[])
{
struct kvm_vcpu *vcpu;
kvm_vm_free(vm);
+ race_sync_regs(race_sregs_cr4);
+
return 0;
}