Re: [PATCH V11 4/5] selftest: KVM: Add open sev dev helper

[Sean Christopherson <seanjc@google.com>]

On Thu, Oct 21, 2021, Peter Gonda wrote:
> diff --git a/tools/testing/selftests/kvm/lib/kvm_util.c b/tools/testing/selftests/kvm/lib/kvm_util.c
> index 10a8ed691c66..06a6c04010fb 100644
> --- a/tools/testing/selftests/kvm/lib/kvm_util.c
> +++ b/tools/testing/selftests/kvm/lib/kvm_util.c
> @@ -31,6 +31,19 @@ static void *align(void *x, size_t size)
>  	return (void *) (((size_t) x + mask) & ~mask);
>  }
>  
> +int open_path_or_exit(const char *path, int flags)
> +{
> +	int fd;
> +
> +	fd = open(path, flags);
> +	if (fd < 0) {
> +		print_skip("%s not available (errno: %d)", path, errno);

While you're here, can you add the strerror(errno) as well?  There are some other
enhancements I'd like to make as some failure modes are really annoying, e.g. if
the max vCPUs test fails/skips due to ulimits, but printing the human friendly
version is an easy one to pick off.

> +		exit(KSFT_SKIP);
> +	}
> +
> +	return fd;
> +}
> +
>  /*
>   * Open KVM_DEV_PATH if available, otherwise exit the entire program.
>   *
> @@ -42,16 +55,7 @@ static void *align(void *x, size_t size)
>   */
>  static int _open_kvm_dev_path_or_exit(int flags)
>  {
> -	int fd;
> -
> -	fd = open(KVM_DEV_PATH, flags);
> -	if (fd < 0) {
> -		print_skip("%s not available, is KVM loaded? (errno: %d)",
> -			   KVM_DEV_PATH, errno);
> -		exit(KSFT_SKIP);
> -	}
> -
> -	return fd;
> +	return open_path_or_exit(KVM_DEV_PATH, flags);
>  }
>  
>  int open_kvm_dev_path_or_exit(void)
> diff --git a/tools/testing/selftests/kvm/lib/x86_64/svm.c b/tools/testing/selftests/kvm/lib/x86_64/svm.c
> index 2ac98d70d02b..14a8618efa9c 100644
> --- a/tools/testing/selftests/kvm/lib/x86_64/svm.c
> +++ b/tools/testing/selftests/kvm/lib/x86_64/svm.c
> @@ -13,6 +13,8 @@
>  #include "processor.h"
>  #include "svm_util.h"
>  
> +#define SEV_DEV_PATH "/dev/sev"
> +
>  struct gpr64_regs guest_regs;
>  u64 rflags;
>  
> @@ -160,3 +162,14 @@ void nested_svm_check_supported(void)
>  		exit(KSFT_SKIP);
>  	}
>  }
> +
> +/*
> + * Open SEV_DEV_PATH if available, otherwise exit the entire program.
> + *
> + * Return:
> + *   The opened file descriptor of /dev/sev.
> + */
> +int open_sev_dev_path_or_exit(void)
> +{
> +	return open_path_or_exit(SEV_DEV_PATH, 0);
> +}
> -- 
> 2.33.0.1079.g6e70778dc9-goog
>