KVM: arm64: Describe RES0/RES1 bits of MDCR_EL2

Add support for sanitising MDCR_EL2 and describe the RES0/RES1 bits
according to the feature set exposed to the VM.

Reviewed-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20241025182354.3364124-6-oliver.upton@linux.dev
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>

Author: oupton

arch/arm64/include/asm/kvm_host.h

@@ -471,7 +471,6 @@ enum vcpu_sysreg {
 	/* EL2 registers */
 	SCTLR_EL2,	/* System Control Register (EL2) */
 	ACTLR_EL2,	/* Auxiliary Control Register (EL2) */
-	MDCR_EL2,	/* Monitor Debug Configuration Register (EL2) */
 	CPTR_EL2,	/* Architectural Feature Trap Register (EL2) */
 	HACR_EL2,	/* Hypervisor Auxiliary Control Register */
 	ZCR_EL2,	/* SVE Control Register (EL2) */
@@ -499,6 +498,7 @@ enum vcpu_sysreg {
 
 	/* Anything from this can be RES0/RES1 sanitised */
 	MARKER(__SANITISED_REG_START__),
+	MDCR_EL2,	/* Monitor Debug Configuration Register (EL2) */
 
 	/* Any VNCR-capable reg goes after this point */
 	MARKER(__VNCR_START__),

arch/arm64/kvm/nested.c

@@ -1211,6 +1211,43 @@ int kvm_init_nv_sysregs(struct kvm *kvm)
 		res0 |= SCTLR_EL1_EPAN;
 	set_sysreg_masks(kvm, SCTLR_EL1, res0, res1);
 
+	/* MDCR_EL2 */
+	res0 = MDCR_EL2_RES0;
+	res1 = MDCR_EL2_RES1;
+	if (!kvm_has_feat(kvm, ID_AA64DFR0_EL1, PMUVer, IMP))
+		res0 |= (MDCR_EL2_HPMN | MDCR_EL2_TPMCR |
+			 MDCR_EL2_TPM | MDCR_EL2_HPME);
+	if (!kvm_has_feat(kvm, ID_AA64DFR0_EL1, PMSVer, IMP))
+		res0 |= MDCR_EL2_E2PB | MDCR_EL2_TPMS;
+	if (!kvm_has_feat(kvm, ID_AA64DFR1_EL1, SPMU, IMP))
+		res0 |= MDCR_EL2_EnSPM;
+	if (!kvm_has_feat(kvm, ID_AA64DFR0_EL1, PMUVer, V3P1))
+		res0 |= MDCR_EL2_HPMD;
+	if (!kvm_has_feat(kvm, ID_AA64DFR0_EL1, TraceFilt, IMP))
+		res0 |= MDCR_EL2_TTRF;
+	if (!kvm_has_feat(kvm, ID_AA64DFR0_EL1, PMUVer, V3P5))
+		res0 |= MDCR_EL2_HCCD | MDCR_EL2_HLP;
+	if (!kvm_has_feat(kvm, ID_AA64DFR0_EL1, TraceBuffer, IMP))
+		res0 |= MDCR_EL2_E2TB;
+	if (!kvm_has_feat(kvm, ID_AA64MMFR0_EL1, FGT, IMP))
+		res0 |= MDCR_EL2_TDCC;
+	if (!kvm_has_feat(kvm, ID_AA64DFR0_EL1, MTPMU, IMP) ||
+	    kvm_has_feat(kvm, ID_AA64PFR0_EL1, EL3, IMP))
+		res0 |= MDCR_EL2_MTPME;
+	if (!kvm_has_feat(kvm, ID_AA64DFR0_EL1, PMUVer, V3P7))
+		res0 |= MDCR_EL2_HPMFZO;
+	if (!kvm_has_feat(kvm, ID_AA64DFR0_EL1, PMSS, IMP))
+		res0 |= MDCR_EL2_PMSSE;
+	if (!kvm_has_feat(kvm, ID_AA64DFR0_EL1, PMSVer, V1P2))
+		res0 |= MDCR_EL2_HPMFZS;
+	if (!kvm_has_feat(kvm, ID_AA64DFR1_EL1, EBEP, IMP))
+		res0 |= MDCR_EL2_PMEE;
+	if (!kvm_has_feat(kvm, ID_AA64DFR0_EL1, DebugVer, V8P9))
+		res0 |= MDCR_EL2_EBWE;
+	if (!kvm_has_feat(kvm, ID_AA64DFR2_EL1, STEP, IMP))
+		res0 |= MDCR_EL2_EnSTEPOP;
+	set_sysreg_masks(kvm, MDCR_EL2, res0, res1);
+
 	return 0;
 }