KVM: selftests: Set input function/index in raw CPUID helper(s)

Set the function/index for CPUID in the helper instead of relying on the
caller to do so.  In addition to reducing the risk of consuming an
uninitialized ECX, having the function/index embedded in the call makes
it easier to understand what is being checked.

Signed-off-by: Sean Christopherson <seanjc@google.com>
Link: https://lore.kernel.org/r/20220614200707.3315957-32-seanjc@google.com

diff --git a/tools/testing/selftests/kvm/include/x86_64/processor.h b/tools/testing/selftests/kvm/include/x86_64/processor.h
index d1c0cff24779990f8799e49392f711899f6e6e24..47e74beda155891dcea11d3b21767846c8d4cc6f 100644 (file)
--- a/tools/testing/selftests/kvm/include/x86_64/processor.h
+++ b/tools/testing/selftests/kvm/include/x86_64/processor.h
@@ -404,10 +404,13 @@ static inline void outl(uint16_t port, uint32_t value)
        __asm__ __volatile__("outl %%eax, %%dx" : : "d"(port), "a"(value));
 }
 
-static inline void cpuid(uint32_t *eax, uint32_t *ebx,
-                        uint32_t *ecx, uint32_t *edx)
+static inline void __cpuid(uint32_t function, uint32_t index,
+                          uint32_t *eax, uint32_t *ebx,
+                          uint32_t *ecx, uint32_t *edx)
 {
-       /* ecx is often an input as well as an output. */
+       *eax = function;
+       *ecx = index;
+
        asm volatile("cpuid"
            : "=a" (*eax),
              "=b" (*ebx),
@@ -417,6 +420,13 @@ static inline void cpuid(uint32_t *eax, uint32_t *ebx,
            : "memory");
 }
 
+static inline void cpuid(uint32_t function,
+                        uint32_t *eax, uint32_t *ebx,
+                        uint32_t *ecx, uint32_t *edx)
+{
+       return __cpuid(function, 0, eax, ebx, ecx, edx);
+}
+
 #define SET_XMM(__var, __xmm) \
        asm volatile("movq %0, %%"#__xmm : : "r"(__var) : #__xmm)
 

diff --git a/tools/testing/selftests/kvm/lib/x86_64/processor.c b/tools/testing/selftests/kvm/lib/x86_64/processor.c
index 8677c60633881715dac96582b5761ea75a8ea21a..5f62b58433d3e035b3e071efb1cbcd98eed044ed 100644 (file)
--- a/tools/testing/selftests/kvm/lib/x86_64/processor.c
+++ b/tools/testing/selftests/kvm/lib/x86_64/processor.c
@@ -1301,9 +1301,7 @@ unsigned long vm_compute_max_gfn(struct kvm_vm *vm)
 
        /* Before family 17h, the HyperTransport area is just below 1T.  */
        ht_gfn = (1 << 28) - num_ht_pages;
-       eax = 1;
-       ecx = 0;
-       cpuid(&eax, &ebx, &ecx, &edx);
+       cpuid(1, &eax, &ebx, &ecx, &edx);
        if (x86_family(eax) < 0x17)
                goto done;
 
@@ -1312,18 +1310,15 @@ unsigned long vm_compute_max_gfn(struct kvm_vm *vm)
         * reduced due to SME by bits 11:6 of CPUID[0x8000001f].EBX.  Use
         * the old conservative value if MAXPHYADDR is not enumerated.
         */
-       eax = 0x80000000;
-       cpuid(&eax, &ebx, &ecx, &edx);
+       cpuid(0x80000000, &eax, &ebx, &ecx, &edx);
        max_ext_leaf = eax;
        if (max_ext_leaf < 0x80000008)
                goto done;
 
-       eax = 0x80000008;
-       cpuid(&eax, &ebx, &ecx, &edx);
+       cpuid(0x80000008, &eax, &ebx, &ecx, &edx);
        max_pfn = (1ULL << ((eax & 0xff) - vm->page_shift)) - 1;
        if (max_ext_leaf >= 0x8000001f) {
-               eax = 0x8000001f;
-               cpuid(&eax, &ebx, &ecx, &edx);
+               cpuid(0x8000001f, &eax, &ebx, &ecx, &edx);
                max_pfn >>= (ebx >> 6) & 0x3f;
        }
 

diff --git a/tools/testing/selftests/kvm/x86_64/amx_test.c b/tools/testing/selftests/kvm/x86_64/amx_test.c
index c8f98331a807bcd78ef949991890f583821782c6..cb5e20936cc1e75ed0edc140f3bdc4a9152db66e 100644 (file)
--- a/tools/testing/selftests/kvm/x86_64/amx_test.c
+++ b/tools/testing/selftests/kvm/x86_64/amx_test.c
@@ -122,9 +122,7 @@ static inline void check_cpuid_xsave(void)
 {
        uint32_t eax, ebx, ecx, edx;
 
-       eax = 1;
-       ecx = 0;
-       cpuid(&eax, &ebx, &ecx, &edx);
+       cpuid(1, &eax, &ebx, &ecx, &edx);
        if (!(ecx & CPUID_XSAVE))
                GUEST_ASSERT(!"cpuid: no CPU xsave support!");
        if (!(ecx & CPUID_OSXSAVE))
@@ -140,10 +138,7 @@ static bool enum_xtile_config(void)
 {
        u32 eax, ebx, ecx, edx;
 
-       eax = TILE_CPUID;
-       ecx = TILE_PALETTE_CPUID_SUBLEAVE;
-
-       cpuid(&eax, &ebx, &ecx, &edx);
+       __cpuid(TILE_CPUID, TILE_PALETTE_CPUID_SUBLEAVE, &eax, &ebx, &ecx, &edx);
        if (!eax || !ebx || !ecx)
                return false;
 
@@ -165,10 +160,7 @@ static bool enum_xsave_tile(void)
 {
        u32 eax, ebx, ecx, edx;
 
-       eax = XSTATE_CPUID;
-       ecx = XFEATURE_XTILEDATA;
-
-       cpuid(&eax, &ebx, &ecx, &edx);
+       __cpuid(XSTATE_CPUID, XFEATURE_XTILEDATA, &eax, &ebx, &ecx, &edx);
        if (!eax || !ebx)
                return false;
 
@@ -183,10 +175,7 @@ static bool check_xsave_size(void)
        u32 eax, ebx, ecx, edx;
        bool valid = false;
 
-       eax = XSTATE_CPUID;
-       ecx = XSTATE_USER_STATE_SUBLEAVE;
-
-       cpuid(&eax, &ebx, &ecx, &edx);
+       __cpuid(XSTATE_CPUID, XSTATE_USER_STATE_SUBLEAVE, &eax, &ebx, &ecx, &edx);
        if (ebx && ebx <= XSAVE_SIZE)
                valid = true;
 

diff --git a/tools/testing/selftests/kvm/x86_64/cpuid_test.c b/tools/testing/selftests/kvm/x86_64/cpuid_test.c
index d8ae4a0e00a4b15ed9355c2a9c31880ec034c688..a6aeee2e62e4f5920432faa2dbb0d431ec5035fa 100644 (file)
--- a/tools/testing/selftests/kvm/x86_64/cpuid_test.c
+++ b/tools/testing/selftests/kvm/x86_64/cpuid_test.c
@@ -31,10 +31,9 @@ static void test_guest_cpuids(struct kvm_cpuid2 *guest_cpuid)
        u32 eax, ebx, ecx, edx;
 
        for (i = 0; i < guest_cpuid->nent; i++) {
-               eax = guest_cpuid->entries[i].function;
-               ecx = guest_cpuid->entries[i].index;
-
-               cpuid(&eax, &ebx, &ecx, &edx);
+               __cpuid(guest_cpuid->entries[i].function,
+                       guest_cpuid->entries[i].index,
+                       &eax, &ebx, &ecx, &edx);
 
                GUEST_ASSERT(eax == guest_cpuid->entries[i].eax &&
                             ebx == guest_cpuid->entries[i].ebx &&
@@ -46,9 +45,9 @@ static void test_guest_cpuids(struct kvm_cpuid2 *guest_cpuid)
 
 static void test_cpuid_40000000(struct kvm_cpuid2 *guest_cpuid)
 {
-       u32 eax = 0x40000000, ebx, ecx = 0, edx;
+       u32 eax, ebx, ecx, edx;
 
-       cpuid(&eax, &ebx, &ecx, &edx);
+       cpuid(0x40000000, &eax, &ebx, &ecx, &edx);
 
        GUEST_ASSERT(eax == 0x40000001);
 }