| Message ID | 1529984517-7843-1-git-send-email-wei@redhat.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
On 26/06/2018 05:41, Wei Huang wrote: > KVM is supposed to update some guest VM's CPUID bits (e.g. OSXSAVE) when > CR4 is changed. A bug was found in KVM recently and it was fixed by > Commit c4d2188206ba ("KVM: x86: Update cpuid properly when CR4.OSXAVE or > CR4.PKE is changed"). This patch adds a test to verify the synchronization > between guest VM's CR4 and CPUID bits. > > Signed-off-by: Wei Huang <wei@redhat.com> > --- > tools/testing/selftests/kvm/Makefile | 1 + > tools/testing/selftests/kvm/cr4_cpuid_sync_test.c | 129 ++++++++++++++++++++++ > 2 files changed, 130 insertions(+) > create mode 100644 tools/testing/selftests/kvm/cr4_cpuid_sync_test.c > > diff --git a/tools/testing/selftests/kvm/Makefile b/tools/testing/selftests/kvm/Makefile > index d9d0031..65bda4f 100644 > --- a/tools/testing/selftests/kvm/Makefile > +++ b/tools/testing/selftests/kvm/Makefile > @@ -9,6 +9,7 @@ LIBKVM_x86_64 = lib/x86.c lib/vmx.c > TEST_GEN_PROGS_x86_64 = set_sregs_test > TEST_GEN_PROGS_x86_64 += sync_regs_test > TEST_GEN_PROGS_x86_64 += vmx_tsc_adjust_test > +TEST_GEN_PROGS_x86_64 += cr4_cpuid_sync_test > > TEST_GEN_PROGS += $(TEST_GEN_PROGS_$(UNAME_M)) > LIBKVM += $(LIBKVM_$(UNAME_M)) > diff --git a/tools/testing/selftests/kvm/cr4_cpuid_sync_test.c b/tools/testing/selftests/kvm/cr4_cpuid_sync_test.c > new file mode 100644 > index 0000000..dbbaf3c > --- /dev/null > +++ b/tools/testing/selftests/kvm/cr4_cpuid_sync_test.c > @@ -0,0 +1,129 @@ > +// SPDX-License-Identifier: GPL-2.0 > +/* > + * CR4 and CPUID sync test > + * > + * Copyright 2018, Red Hat, Inc. and/or its affiliates. > + * > + * Author: > + * Wei Huang <wei@redhat.com> > + */ > + > +#include <fcntl.h> > +#include <stdio.h> > +#include <stdlib.h> > +#include <string.h> > +#include <sys/ioctl.h> > + > +#include "test_util.h" > + > +#include "kvm_util.h" > +#include "x86.h" > + > +#define X86_FEATURE_XSAVE (1<<26) > +#define X86_FEATURE_OSXSAVE (1<<27) > +#define VCPU_ID 1 > + > +enum { > + GUEST_UPDATE_CR4 = 0x1000, > + GUEST_FAILED, > + GUEST_DONE, > +}; > + > +static void exit_to_hv(uint16_t port) > +{ > + __asm__ __volatile__("in %[port], %%al" > + : > + : [port]"d"(port) > + : "rax"); > +} > + > +static inline bool cr4_cpuid_is_sync(void) > +{ > + int func, subfunc; > + uint32_t eax, ebx, ecx, edx; > + uint64_t cr4; > + > + func = 0x1; > + subfunc = 0x0; > + __asm__ __volatile__("cpuid" > + : "=a"(eax), "=b"(ebx), "=c"(ecx), "=d"(edx) > + : "a"(func), "c"(subfunc)); > + > + cr4 = get_cr4(); > + > + return (!!(ecx & X86_FEATURE_OSXSAVE)) == (!!(cr4 & X86_CR4_OSXSAVE)); > +} > + > +static void guest_code(void) > +{ > + uint64_t cr4; > + > + /* turn on CR4.OSXSAVE */ > + cr4 = get_cr4(); > + cr4 |= X86_CR4_OSXSAVE; > + set_cr4(cr4); > + > + /* verify CR4.OSXSAVE == CPUID.OSXSAVE */ > + if (!cr4_cpuid_is_sync()) > + exit_to_hv(GUEST_FAILED); > + > + /* notify hypervisor to change CR4 */ > + exit_to_hv(GUEST_UPDATE_CR4); > + > + /* check again */ > + if (!cr4_cpuid_is_sync()) > + exit_to_hv(GUEST_FAILED); > + > + exit_to_hv(GUEST_DONE); > +} > + > +int main(int argc, char *argv[]) > +{ > + struct kvm_run *run; > + struct kvm_vm *vm; > + struct kvm_sregs sregs; > + struct kvm_cpuid_entry2 *entry; > + int rc; > + > + entry = kvm_get_supported_cpuid_entry(1); > + if (!(entry->ecx & X86_FEATURE_XSAVE)) { > + printf("XSAVE feature not supported, skipping test\n"); > + return 0; > + } > + > + /* Tell stdout not to buffer its content */ > + setbuf(stdout, NULL); > + > + /* Create VM */ > + vm = vm_create_default_vmx(VCPU_ID, guest_code); > + vcpu_set_cpuid(vm, VCPU_ID, kvm_get_supported_cpuid()); > + run = vcpu_state(vm, VCPU_ID); > + > + while (1) { > + rc = _vcpu_run(vm, VCPU_ID); > + > + if (run->exit_reason == KVM_EXIT_IO) { > + switch (run->io.port) { > + case GUEST_UPDATE_CR4: > + /* emulate hypervisor clearing CR4.OSXSAVE */ > + vcpu_sregs_get(vm, VCPU_ID, &sregs); > + sregs.cr4 &= ~X86_CR4_OSXSAVE; > + vcpu_sregs_set(vm, VCPU_ID, &sregs); > + break; > + case GUEST_FAILED: > + TEST_ASSERT(false, "Guest CR4 bit (OSXSAVE) unsynchronized with CPUID bit."); > + break; > + case GUEST_DONE: > + goto done; > + default: > + TEST_ASSERT(false, "Unknown port 0x%x.", > + run->io.port); > + } > + } > + } > + > + kvm_vm_free(vm); > + > +done: > + return 0; > +} > Queued, thanks. Paolo -- To unsubscribe from this list: send the line "unsubscribe linux-kselftest" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/tools/testing/selftests/kvm/Makefile b/tools/testing/selftests/kvm/Makefile index d9d0031..65bda4f 100644 --- a/tools/testing/selftests/kvm/Makefile +++ b/tools/testing/selftests/kvm/Makefile @@ -9,6 +9,7 @@ LIBKVM_x86_64 = lib/x86.c lib/vmx.c TEST_GEN_PROGS_x86_64 = set_sregs_test TEST_GEN_PROGS_x86_64 += sync_regs_test TEST_GEN_PROGS_x86_64 += vmx_tsc_adjust_test +TEST_GEN_PROGS_x86_64 += cr4_cpuid_sync_test TEST_GEN_PROGS += $(TEST_GEN_PROGS_$(UNAME_M)) LIBKVM += $(LIBKVM_$(UNAME_M)) diff --git a/tools/testing/selftests/kvm/cr4_cpuid_sync_test.c b/tools/testing/selftests/kvm/cr4_cpuid_sync_test.c new file mode 100644 index 0000000..dbbaf3c --- /dev/null +++ b/tools/testing/selftests/kvm/cr4_cpuid_sync_test.c @@ -0,0 +1,129 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * CR4 and CPUID sync test + * + * Copyright 2018, Red Hat, Inc. and/or its affiliates. + * + * Author: + * Wei Huang <wei@redhat.com> + */ + +#include <fcntl.h> +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <sys/ioctl.h> + +#include "test_util.h" + +#include "kvm_util.h" +#include "x86.h" + +#define X86_FEATURE_XSAVE (1<<26) +#define X86_FEATURE_OSXSAVE (1<<27) +#define VCPU_ID 1 + +enum { + GUEST_UPDATE_CR4 = 0x1000, + GUEST_FAILED, + GUEST_DONE, +}; + +static void exit_to_hv(uint16_t port) +{ + __asm__ __volatile__("in %[port], %%al" + : + : [port]"d"(port) + : "rax"); +} + +static inline bool cr4_cpuid_is_sync(void) +{ + int func, subfunc; + uint32_t eax, ebx, ecx, edx; + uint64_t cr4; + + func = 0x1; + subfunc = 0x0; + __asm__ __volatile__("cpuid" + : "=a"(eax), "=b"(ebx), "=c"(ecx), "=d"(edx) + : "a"(func), "c"(subfunc)); + + cr4 = get_cr4(); + + return (!!(ecx & X86_FEATURE_OSXSAVE)) == (!!(cr4 & X86_CR4_OSXSAVE)); +} + +static void guest_code(void) +{ + uint64_t cr4; + + /* turn on CR4.OSXSAVE */ + cr4 = get_cr4(); + cr4 |= X86_CR4_OSXSAVE; + set_cr4(cr4); + + /* verify CR4.OSXSAVE == CPUID.OSXSAVE */ + if (!cr4_cpuid_is_sync()) + exit_to_hv(GUEST_FAILED); + + /* notify hypervisor to change CR4 */ + exit_to_hv(GUEST_UPDATE_CR4); + + /* check again */ + if (!cr4_cpuid_is_sync()) + exit_to_hv(GUEST_FAILED); + + exit_to_hv(GUEST_DONE); +} + +int main(int argc, char *argv[]) +{ + struct kvm_run *run; + struct kvm_vm *vm; + struct kvm_sregs sregs; + struct kvm_cpuid_entry2 *entry; + int rc; + + entry = kvm_get_supported_cpuid_entry(1); + if (!(entry->ecx & X86_FEATURE_XSAVE)) { + printf("XSAVE feature not supported, skipping test\n"); + return 0; + } + + /* Tell stdout not to buffer its content */ + setbuf(stdout, NULL); + + /* Create VM */ + vm = vm_create_default_vmx(VCPU_ID, guest_code); + vcpu_set_cpuid(vm, VCPU_ID, kvm_get_supported_cpuid()); + run = vcpu_state(vm, VCPU_ID); + + while (1) { + rc = _vcpu_run(vm, VCPU_ID); + + if (run->exit_reason == KVM_EXIT_IO) { + switch (run->io.port) { + case GUEST_UPDATE_CR4: + /* emulate hypervisor clearing CR4.OSXSAVE */ + vcpu_sregs_get(vm, VCPU_ID, &sregs); + sregs.cr4 &= ~X86_CR4_OSXSAVE; + vcpu_sregs_set(vm, VCPU_ID, &sregs); + break; + case GUEST_FAILED: + TEST_ASSERT(false, "Guest CR4 bit (OSXSAVE) unsynchronized with CPUID bit."); + break; + case GUEST_DONE: + goto done; + default: + TEST_ASSERT(false, "Unknown port 0x%x.", + run->io.port); + } + } + } + + kvm_vm_free(vm); + +done: + return 0; +}
KVM is supposed to update some guest VM's CPUID bits (e.g. OSXSAVE) when CR4 is changed. A bug was found in KVM recently and it was fixed by Commit c4d2188206ba ("KVM: x86: Update cpuid properly when CR4.OSXAVE or CR4.PKE is changed"). This patch adds a test to verify the synchronization between guest VM's CR4 and CPUID bits. Signed-off-by: Wei Huang <wei@redhat.com> --- tools/testing/selftests/kvm/Makefile | 1 + tools/testing/selftests/kvm/cr4_cpuid_sync_test.c | 129 ++++++++++++++++++++++ 2 files changed, 130 insertions(+) create mode 100644 tools/testing/selftests/kvm/cr4_cpuid_sync_test.c