diff mbox series

[RFC,1/7] arm64: cpufeature: Add API to report system support of HWDBM

Message ID 20210126124444.27136-2-zhukeqian1@huawei.com (mailing list archive)
State New, archived
Headers show
Series kvm: arm64: Implement SW/HW combined dirty log | expand

Commit Message

zhukeqian Jan. 26, 2021, 12:44 p.m. UTC
Though we already has a cpu capability named ARM64_HW_DBM, it's a
LOCAL_CPU cap and conditionally compiled by CONFIG_ARM64_HW_AFDBM.

This reports the system wide support of HW_DBM.

Signed-off-by: Keqian Zhu <zhukeqian1@huawei.com>
---
 arch/arm64/include/asm/cpufeature.h | 12 ++++++++++++
 1 file changed, 12 insertions(+)
diff mbox series

Patch

diff --git a/arch/arm64/include/asm/cpufeature.h b/arch/arm64/include/asm/cpufeature.h
index 9a555809b89c..dfded86c7684 100644
--- a/arch/arm64/include/asm/cpufeature.h
+++ b/arch/arm64/include/asm/cpufeature.h
@@ -664,6 +664,18 @@  static inline bool system_supports_mixed_endian(void)
 	return val == 0x1;
 }
 
+static inline bool system_supports_hw_dbm(void)
+{
+	u64 mmfr1;
+	u32 val;
+
+	mmfr1 = read_sanitised_ftr_reg(SYS_ID_AA64MMFR1_EL1);
+	val = cpuid_feature_extract_unsigned_field(mmfr1,
+						ID_AA64MMFR1_HADBS_SHIFT);
+
+	return val == 0x2;
+}
+
 static __always_inline bool system_supports_fpsimd(void)
 {
 	return !cpus_have_const_cap(ARM64_HAS_NO_FPSIMD);