[PATCH v7 06/12] KVM: arm64: Add flag for FEAT_TRF

[James Clark]

From: James Clark <james.clark@xxxxxxx>

FEAT_TRF can control trace generation at different ELs so this will
enable support of exclude/include guest rules when it's present without
TRBE. With TRBE we'll have to continue to always disable guest trace.

Signed-off-by: James Clark <james.clark@xxxxxxx>
Signed-off-by: James Clark <james.clark@xxxxxxxxxx>
---
 arch/arm64/include/asm/kvm_host.h |  2 ++
 arch/arm64/kvm/debug.c            | 14 ++++++++++----
 2 files changed, 12 insertions(+), 4 deletions(-)

diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
index 61ff34e1ffef..5dfc3f4f74b2 100644
--- a/arch/arm64/include/asm/kvm_host.h
+++ b/arch/arm64/include/asm/kvm_host.h
@@ -939,6 +939,8 @@ struct kvm_vcpu_arch {
 #define HOST_FEAT_HAS_SPE	__kvm_single_flag(feats, BIT(0))
 /* Save TRBE context if active  */
 #define HOST_FEAT_HAS_TRBE	__kvm_single_flag(feats, BIT(1))
+/* CPU has Feat_TRF */
+#define HOST_FEAT_HAS_TRF	__kvm_single_flag(feats, BIT(2))
 
 /* Pointer to the vcpu's SVE FFR for sve_{save,load}_state() */
 #define vcpu_sve_pffr(vcpu) (kern_hyp_va((vcpu)->arch.sve_state) +	\
diff --git a/arch/arm64/kvm/debug.c b/arch/arm64/kvm/debug.c
index cf5558806687..fb41ef5d9db9 100644
--- a/arch/arm64/kvm/debug.c
+++ b/arch/arm64/kvm/debug.c
@@ -89,10 +89,16 @@ void kvm_arm_init_debug(void)
 	    !(read_sysreg_s(SYS_PMBIDR_EL1) & BIT(PMBIDR_EL1_P_SHIFT)))
 		host_data_set_flag(HOST_FEAT_HAS_SPE);
 
-	/* Check if we have TRBE implemented and available at the host */
-	if (cpuid_feature_extract_unsigned_field(dfr0, ID_AA64DFR0_EL1_TraceBuffer_SHIFT) &&
-	    !(read_sysreg_s(SYS_TRBIDR_EL1) & TRBIDR_EL1_P))
-		host_data_set_flag(HOST_FEAT_HAS_TRBE);
+	if (cpuid_feature_extract_unsigned_field(dfr0, ID_AA64DFR0_EL1_TraceFilt_SHIFT)) {
+		host_data_set_flag(HOST_FEAT_HAS_TRF);
+		/*
+		 * The architecture mandates FEAT_TRF with TRBE, so only need to check
+		 * for TRBE if TRF exists.
+		 */
+		if (cpuid_feature_extract_unsigned_field(dfr0, ID_AA64DFR0_EL1_TraceBuffer_SHIFT) &&
+		    !(read_sysreg_s(SYS_TRBIDR_EL1) & TRBIDR_EL1_P))
+			host_data_set_flag(HOST_FEAT_HAS_TRBE);
+	}
 }
 
 /**
-- 
2.34.1