KVM: selftests: Check that the palette table exists before using it

Check that the palette table exists before using it. The maximum number of
AMX palette tables is enumerated by CPUID.1DH:EAX. Assert that the palette
used in amx_test, CPUID.1DH.1H, does not exceed that maximum.

Signed-off-by: Aaron Lewis <aaronlewis@google.com>
Signed-off-by: Mingwei Zhang <mizhang@google.com>
Link: https://lore.kernel.org/r/20230221163655.920289-13-mizhang@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>

Author: suomilewis

tools/testing/selftests/kvm/include/x86_64/processor.h

@@ -227,6 +227,7 @@ struct kvm_x86_cpu_property {
 #define X86_PROPERTY_XSTATE_MAX_SIZE		KVM_X86_CPU_PROPERTY(0xd,  0, ECX,  0, 31)
 #define X86_PROPERTY_XSTATE_TILE_SIZE		KVM_X86_CPU_PROPERTY(0xd, 18, EAX,  0, 31)
 #define X86_PROPERTY_XSTATE_TILE_OFFSET		KVM_X86_CPU_PROPERTY(0xd, 18, EBX,  0, 31)
+#define X86_PROPERTY_AMX_MAX_PALETTE_TABLES	KVM_X86_CPU_PROPERTY(0x1d, 0, EAX,  0, 31)
 #define X86_PROPERTY_AMX_TOTAL_TILE_BYTES	KVM_X86_CPU_PROPERTY(0x1d, 1, EAX,  0, 15)
 #define X86_PROPERTY_AMX_BYTES_PER_TILE		KVM_X86_CPU_PROPERTY(0x1d, 1, EAX, 16, 31)
 #define X86_PROPERTY_AMX_BYTES_PER_ROW		KVM_X86_CPU_PROPERTY(0x1d, 1, EBX, 0,  15)

tools/testing/selftests/kvm/x86_64/amx_test.c

@@ -30,6 +30,7 @@
 #define XSAVE_SIZE			((NUM_TILES * TILE_SIZE) + PAGE_SIZE)
 
 /* Tile configuration associated: */
+#define PALETTE_TABLE_INDEX		1
 #define MAX_TILES			16
 #define RESERVED_BYTES			14
 
@@ -120,6 +121,10 @@ static void check_xtile_info(void)
 	GUEST_ASSERT(xtile.xsave_size == 8192);
 	GUEST_ASSERT(sizeof(struct tile_data) >= xtile.xsave_size);
 
+	GUEST_ASSERT(this_cpu_has_p(X86_PROPERTY_AMX_MAX_PALETTE_TABLES));
+	GUEST_ASSERT(this_cpu_property(X86_PROPERTY_AMX_MAX_PALETTE_TABLES) >=
+		     PALETTE_TABLE_INDEX);
+
 	GUEST_ASSERT(this_cpu_has_p(X86_PROPERTY_AMX_NR_TILE_REGS));
 	xtile.max_names = this_cpu_property(X86_PROPERTY_AMX_NR_TILE_REGS);
 	GUEST_ASSERT(xtile.max_names == 8);