On 30/09/20 06:34, Sean Christopherson wrote:
> Add an i386-only test to check that setting CR4.LA57 fails when 5-level
> paging is not exposed to the guest. Old versions of KVM don't intercept
> LA57 by default on VMX, which means a clever guest could set LA57
> without it being detected by KVM.
>
> This test is i386-only because toggling CR4.LA57 in long mode is
> illegal, i.e. won't verify the desired KVM behavior.
>
> Signed-off-by: Sean Christopherson <sean.j.christopherson@xxxxxxxxx>
> ---
> x86/Makefile.i386 | 2 +-
> x86/la57.c | 13 +++++++++++++
> x86/unittests.cfg | 4 ++++
> 3 files changed, 18 insertions(+), 1 deletion(-)
> create mode 100644 x86/la57.c
>
> diff --git a/x86/Makefile.i386 b/x86/Makefile.i386
> index be9d6bc..c04e5aa 100644
> --- a/x86/Makefile.i386
> +++ b/x86/Makefile.i386
> @@ -6,6 +6,6 @@ COMMON_CFLAGS += -mno-sse -mno-sse2
> cflatobjs += lib/x86/setjmp32.o
>
> tests = $(TEST_DIR)/taskswitch.flat $(TEST_DIR)/taskswitch2.flat \
> - $(TEST_DIR)/cmpxchg8b.flat
> + $(TEST_DIR)/cmpxchg8b.flat $(TEST_DIR)/la57.flat
>
> include $(SRCDIR)/$(TEST_DIR)/Makefile.common
> diff --git a/x86/la57.c b/x86/la57.c
> new file mode 100644
> index 0000000..b537bb2
> --- /dev/null
> +++ b/x86/la57.c
> @@ -0,0 +1,13 @@
> +#include "libcflat.h"
> +#include "processor.h"
> +#include "desc.h"
> +
> +int main(int ac, char **av)
> +{
> + int vector = write_cr4_checking(read_cr4() | X86_CR4_LA57);
> + int expected = this_cpu_has(X86_FEATURE_LA57) ? 0 : 13;
> +
> + report(vector == expected, "%s when CR4.LA57 %ssupported",
> + expected ? "#GP" : "No fault", expected ? "un" : "");
> + return report_summary();
> +}
> diff --git a/x86/unittests.cfg b/x86/unittests.cfg
> index 3a79151..6eb8e19 100644
> --- a/x86/unittests.cfg
> +++ b/x86/unittests.cfg
> @@ -245,6 +245,10 @@ arch = x86_64
> file = umip.flat
> extra_params = -cpu qemu64,+umip
>
> +[la57]
> +file = la57.flat
> +arch = i386
> +
> [vmx]
> file = vmx.flat
> extra_params = -cpu host,+vmx -append "-exit_monitor_from_l2_test -ept_access* -vmx_smp* -vmx_vmcs_shadow_test -atomic_switch_overflow_msrs_test -vmx_init_signal_test -vmx_apic_passthrough_tpr_threshold_test"
>
Applied, thanks.
Paolo
