On Thu, Jul 15, 2021, Krish Sadhukhan wrote:
> Current implementation of svm_vmrun() and test_run() sets the guest RIP to a
> wrapper function which executes the guest code being used by tests. This is
> not suitable for tests like testing the effect of guest EFLAGS.TF on VMRUN
> because the trap handler will point to the second guest instruction to which
> the test code does not have access.
>
> Therefore, add a variant of svm_vmrun() that will set the guest RIP to the
> actual guest code that tests want to test. This will be used by the next
> patch in this series.
>
> Signed-off-by: Krish Sadhukhan <krish.sadhukhan@xxxxxxxxxx>
> ---
> x86/svm.c | 14 ++++++++++++--
> x86/svm.h | 1 +
> 2 files changed, 13 insertions(+), 2 deletions(-)
>
> diff --git a/x86/svm.c b/x86/svm.c
> index f185ca0..50b6a15 100644
> --- a/x86/svm.c
> +++ b/x86/svm.c
> @@ -227,9 +227,9 @@ struct svm_test *v2_test;
>
> u64 guest_stack[10000];
>
> -int svm_vmrun(void)
> +static int _svm_vmrun(u64 rip)
I'd prefer to stay with the kernel style of two underscores for inner helpers.
> {
> - vmcb->save.rip = (ulong)test_thunk;
> + vmcb->save.rip = (ulong)rip;
> vmcb->save.rsp = (ulong)(guest_stack + ARRAY_SIZE(guest_stack));
> regs.rdi = (ulong)v2_test;
>
> @@ -244,6 +244,16 @@ int svm_vmrun(void)
> return (vmcb->control.exit_code);
> }
>
> +int svm_vmrun(void)
> +{
> + return _svm_vmrun((u64)test_thunk);
> +}
> +
> +int svm_vmrun_custom(u64 rip)
> +{
> + return _svm_vmrun(rip);
> +}
Why bother with the "custom" wrapper? Just expose the inner helper.
