On Wed, Oct 15, 2025, Yosry Ahmed wrote: > On Wed, Sep 17, 2025 at 02:48:39PM -0700, Jim Mattson wrote: > > Add a new VM mode, VM_MODE_PXXV57_4K, to support tests that require > > 5-level paging on x86. This mode sets up a 57-bit virtual address > > space and sets CR4.LA57 in the guest. > > > > Signed-off-by: Jim Mattson <[email protected]> > > --- > > .../testing/selftests/kvm/include/kvm_util.h | 1 + > > tools/testing/selftests/kvm/lib/kvm_util.c | 21 +++++++++++++++++ > > .../testing/selftests/kvm/lib/x86/processor.c | 23 ++++++++++++------- > > tools/testing/selftests/kvm/lib/x86/vmx.c | 7 +++--- > > 4 files changed, 41 insertions(+), 11 deletions(-) > > > > diff --git a/tools/testing/selftests/kvm/include/kvm_util.h > > b/tools/testing/selftests/kvm/include/kvm_util.h > > index 23a506d7eca3..b6ea5d966715 100644 > > --- a/tools/testing/selftests/kvm/include/kvm_util.h > > +++ b/tools/testing/selftests/kvm/include/kvm_util.h > > @@ -175,6 +175,7 @@ enum vm_guest_mode { > > VM_MODE_P40V48_16K, > > VM_MODE_P40V48_64K, > > VM_MODE_PXXV48_4K, /* For 48bits VA but ANY bits PA */ > > + VM_MODE_PXXV57_4K, /* For 48bits VA but ANY bits PA */ > > VM_MODE_P47V64_4K, > > VM_MODE_P44V64_4K, > > VM_MODE_P36V48_4K, > > diff --git a/tools/testing/selftests/kvm/lib/kvm_util.c > > b/tools/testing/selftests/kvm/lib/kvm_util.c > > index c3f5142b0a54..6b0e499c6e91 100644 > > --- a/tools/testing/selftests/kvm/lib/kvm_util.c > > +++ b/tools/testing/selftests/kvm/lib/kvm_util.c > > @@ -232,6 +232,7 @@ const char *vm_guest_mode_string(uint32_t i) > > [VM_MODE_P40V48_16K] = "PA-bits:40, VA-bits:48, 16K pages", > > [VM_MODE_P40V48_64K] = "PA-bits:40, VA-bits:48, 64K pages", > > [VM_MODE_PXXV48_4K] = "PA-bits:ANY, VA-bits:48, 4K pages", > > + [VM_MODE_PXXV57_4K] = "PA-bits:ANY, VA-bits:57, 4K pages", > > [VM_MODE_P47V64_4K] = "PA-bits:47, VA-bits:64, 4K pages", > > [VM_MODE_P44V64_4K] = "PA-bits:44, VA-bits:64, 4K pages", > > [VM_MODE_P36V48_4K] = "PA-bits:36, VA-bits:48, 4K pages", > > @@ -259,6 +260,7 @@ const struct vm_guest_mode_params > > vm_guest_mode_params[] = { > > [VM_MODE_P40V48_16K] = { 40, 48, 0x4000, 14 }, > > [VM_MODE_P40V48_64K] = { 40, 48, 0x10000, 16 }, > > [VM_MODE_PXXV48_4K] = { 0, 0, 0x1000, 12 }, > > + [VM_MODE_PXXV57_4K] = { 0, 0, 0x1000, 12 }, > > [VM_MODE_P47V64_4K] = { 47, 64, 0x1000, 12 }, > > [VM_MODE_P44V64_4K] = { 44, 64, 0x1000, 12 }, > > [VM_MODE_P36V48_4K] = { 36, 48, 0x1000, 12 }, > > @@ -358,6 +360,25 @@ struct kvm_vm *____vm_create(struct vm_shape shape) > > vm->va_bits = 48; > > #else > > TEST_FAIL("VM_MODE_PXXV48_4K not supported on non-x86 > > platforms"); > > We should probably update TEST_ASSERT(vm->va_bits == 48 || vm->va_bits == 57) > above to only assert 48 bits now, right?
No, because CPUID reports the _max_ virtual address width. In theory, the assert could be ">= 48", but in practice x86-64 only supports 48-bit and 57-bit VAs, so selftests are paranoid and are sanity checking KVM at the same time.
