Re: [PATCH 2/2] selftests/x86/amx: Fix the test to avoid failure when AMX is unavailable

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



On 4/1/22 4:10 PM, Chang S. Bae wrote:
When a CPU does not have AMX, the test fails. But this is wrong as it
should be runnable regardless. Skip the test instead.

Reported-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Fixes: 6a3e0651b4a ("selftests/x86/amx: Add test cases for AMX state management")
Signed-off-by: Chang S. Bae <chang.seok.bae@xxxxxxxxx>
Cc: linux-kselftest@xxxxxxxxxxxxxxx
Cc: linux-kernel@xxxxxxxxxxxxxxx
---
  tools/testing/selftests/x86/amx.c | 42 +++++++++++++++++++++++--------
  1 file changed, 31 insertions(+), 11 deletions(-)

diff --git a/tools/testing/selftests/x86/amx.c b/tools/testing/selftests/x86/amx.c
index 3615ef4a48bb..14abb6072a7d 100644
--- a/tools/testing/selftests/x86/amx.c
+++ b/tools/testing/selftests/x86/amx.c
@@ -106,6 +106,12 @@ static void clearhandler(int sig)
#define CPUID_LEAF1_ECX_XSAVE_MASK (1 << 26)
  #define CPUID_LEAF1_ECX_OSXSAVE_MASK	(1 << 27)
+
+static struct {
+	unsigned xsave:   1;
+	unsigned osxsave: 1;
+} cpuinfo;
+

Why is this needed? Also naming this cpuinfo is confuing.

  static inline void check_cpuid_xsave(void)
  {
  	uint32_t eax, ebx, ecx, edx;
@@ -118,10 +124,8 @@ static inline void check_cpuid_xsave(void)
  	eax = 1;
  	ecx = 0;
  	cpuid(&eax, &ebx, &ecx, &edx);
-	if (!(ecx & CPUID_LEAF1_ECX_XSAVE_MASK))
-		fatal_error("cpuid: no CPU xsave support");
-	if (!(ecx & CPUID_LEAF1_ECX_OSXSAVE_MASK))
-		fatal_error("cpuid: no OS xsave support");
+	cpuinfo.xsave = !!(ecx & CPUID_LEAF1_ECX_XSAVE_MASK);
+	cpuinfo.osxsave = !!(ecx & CPUID_LEAF1_ECX_OSXSAVE_MASK);

Why add this complexity. Why not just Skip here?

  }
static uint32_t xbuf_size;
@@ -161,14 +165,31 @@ static void check_cpuid_xtiledata(void)
  	 * eax: XTILEDATA state component size
  	 * ebx: XTILEDATA state component offset in user buffer
  	 */
-	if (!eax || !ebx)
-		fatal_error("xstate cpuid: invalid tile data size/offset: %d/%d",
-				eax, ebx);
-
  	xtiledata.size	      = eax;
  	xtiledata.xbuf_offset = ebx;
  }
+static bool amx_available(void)
+{
+	check_cpuid_xsave();
+	if (!cpuinfo.xsave) {
+		printf("[SKIP]\tcpuid: no CPU xsave support\n");
+		return false;
+	} else if (!cpuinfo.osxsave) {
+		printf("[SKIP]\tcpuid: no OS xsave support\n");
+		return false;
+	}
+
+	check_cpuid_xtiledata();
+	if (!xtiledata.size || !xtiledata.xbuf_offset) {
+		printf("[SKIP]\txstate cpuid: no tile data (size/offset: %d/%d)\n",
+		       xtiledata.size, xtiledata.xbuf_offset);
+		return false;
+	}
+
+	return true;
+}
+

I am not seeing any value in adding this layer of abstraction.
Keep it simple and do the handling in main()

  /* The helpers for managing XSAVE buffer and tile states: */
struct xsave_buffer *alloc_xbuf(void)
@@ -826,9 +847,8 @@ static void test_context_switch(void)
int main(void)
  {
-	/* Check hardware availability at first */
-	check_cpuid_xsave();
-	check_cpuid_xtiledata();
+	if (!amx_available())
+		return 0;

This should KSFT_SKIP for this to be reported as a skip. Returning 0
will be reported as a Pass.

init_stashed_xsave();
  	sethandler(SIGILL, handle_noperm, 0);


thanks,
-- Shuah



[Index of Archives]     [Linux Wireless]     [Linux Kernel]     [ATH6KL]     [Linux Bluetooth]     [Linux Netdev]     [Kernel Newbies]     [Share Photos]     [IDE]     [Security]     [Git]     [Netfilter]     [Bugtraq]     [Yosemite News]     [MIPS Linux]     [ARM Linux]     [Linux Security]     [Linux RAID]     [Linux ATA RAID]     [Samba]     [Device Mapper]

  Powered by Linux