KVM: arm64: selftests: Use FIELD_GET() to extract ID register fields

Use FIELD_GET() macro to extract ID register fields for existing
aarch64 selftests code. No functional change intended.
Signed-off-by: Reiji Watanabe <reijiw@google.com>
Reviewed-by: Oliver Upton <oliver.upton@linux.dev>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20221020054202.2119018-2-reijiw@google.com

tools/testing/selftests/kvm/aarch64/aarch32_id_regs.c

@@ -13,6 +13,7 @@
 #include "kvm_util.h"
 #include "processor.h"
 #include "test_util.h"
+#include <linux/bitfield.h>
 
 #define BAD_ID_REG_VAL	0x1badc0deul
 
@@ -145,7 +146,7 @@ static bool vcpu_aarch64_only(struct kvm_vcpu *vcpu)
 
 	vcpu_get_reg(vcpu, KVM_ARM64_SYS_REG(SYS_ID_AA64PFR0_EL1), &val);
 
-	el0 = (val & ARM64_FEATURE_MASK(ID_AA64PFR0_EL0)) >> ID_AA64PFR0_EL0_SHIFT;
+	el0 = FIELD_GET(ARM64_FEATURE_MASK(ID_AA64PFR0_EL0), val);
 	return el0 == ID_AA64PFR0_ELx_64BIT_ONLY;
 }
 

tools/testing/selftests/kvm/aarch64/debug-exceptions.c

@@ -2,6 +2,7 @@
 #include <test_util.h>
 #include <kvm_util.h>
 #include <processor.h>
+#include <linux/bitfield.h>
 
 #define MDSCR_KDE	(1 << 13)
 #define MDSCR_MDE	(1 << 15)
@@ -284,7 +285,7 @@ static int debug_version(struct kvm_vcpu *vcpu)
 	uint64_t id_aa64dfr0;
 
 	vcpu_get_reg(vcpu, KVM_ARM64_SYS_REG(SYS_ID_AA64DFR0_EL1), &id_aa64dfr0);
-	return id_aa64dfr0 & 0xf;
+	return FIELD_GET(ARM64_FEATURE_MASK(ID_AA64DFR0_DEBUGVER), id_aa64dfr0);
 }
 
 static void test_guest_debug_exceptions(void)

tools/testing/selftests/kvm/lib/aarch64/processor.c

@@ -11,6 +11,7 @@
 #include "guest_modes.h"
 #include "kvm_util.h"
 #include "processor.h"
+#include <linux/bitfield.h>
 
 #define DEFAULT_ARM64_GUEST_STACK_VADDR_MIN	0xac0000
 
@@ -486,9 +487,9 @@ void aarch64_get_supported_page_sizes(uint32_t ipa,
 	err = ioctl(vcpu_fd, KVM_GET_ONE_REG, &reg);
 	TEST_ASSERT(err == 0, KVM_IOCTL_ERROR(KVM_GET_ONE_REG, vcpu_fd));
 
-	*ps4k = ((val >> 28) & 0xf) != 0xf;
-	*ps64k = ((val >> 24) & 0xf) == 0;
-	*ps16k = ((val >> 20) & 0xf) != 0;
+	*ps4k = FIELD_GET(ARM64_FEATURE_MASK(ID_AA64MMFR0_TGRAN4), val) != 0xf;
+	*ps64k = FIELD_GET(ARM64_FEATURE_MASK(ID_AA64MMFR0_TGRAN64), val) == 0;
+	*ps16k = FIELD_GET(ARM64_FEATURE_MASK(ID_AA64MMFR0_TGRAN16), val) != 0;
 
 	close(vcpu_fd);
 	close(vm_fd);