On 6/16/2022 3:54 PM, Shuah Khan wrote:
On 4/1/22 4:10 PM, Chang S. Bae wrote:
+
+static struct {
+ unsigned xsave: 1;
+ unsigned osxsave: 1;
+} cpuinfo;
+
Why is this needed? Also naming this cpuinfo is confuing.
This came from the below CPUID check which seems to be moot.
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?
I think these CPUID checks can go away with ARCH_GET_XCOMP_SUPP.
}
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()
Sure.
/* 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.
I think that's a good point, thanks.
Now, along with the on-going documentation [1], this test code can be
simplified like the below changes, instead of having those cpuid functions:
diff --git a/tools/testing/selftests/x86/amx.c
b/tools/testing/selftests/x86/amx.c
index 625e42901237..83705c472a5c 100644
--- a/tools/testing/selftests/x86/amx.c
+++ b/tools/testing/selftests/x86/amx.c
@@ -348,6 +348,7 @@ enum expected_result { FAIL_EXPECTED,
SUCCESS_EXPECTED };
/* arch_prctl() and sigaltstack() test */
+#define ARCH_GET_XCOMP_SUPP 0x1021
#define ARCH_GET_XCOMP_PERM 0x1022
#define ARCH_REQ_XCOMP_PERM 0x1023
@@ -828,9 +829,14 @@ static void test_context_switch(void)
int main(void)
{
- /* Check hardware availability at first */
- check_cpuid_xsave();
- check_cpuid_xtiledata();
+ unsigned long features;
+ long rc;
+
+ rc = syscall(SYS_arch_prctl, ARCH_GET_XCOMP_SUPP, &features);
+ if (rc || (features & XFEATURE_MASK_XTILE) != XFEATURE_MASK_XTILE) {
+ printf("[SKIP]\tno AMX support\n");
+ exit(KSFT_FAIL);
+ }
init_stashed_xsave();
sethandler(SIGILL, handle_noperm, 0);
Thanks,
Chang
[1]
https://lore.kernel.org/lkml/86952726-53e6-17a9-dbe0-3e970c565044@xxxxxxxxx/
