KVM: arm64: Handle TSB CSYNC traps

The architecture introduces a trap for TSB CSYNC that fits in
the same EC as LS64 and PSB CSYNC. Let's deal with it in a similar
way.

It's not that we expect this to be useful any time soon anyway.

Signed-off-by: Marc Zyngier <maz@kernel.org>

Author: Marc Zyngier

arch/arm64/include/asm/esr.h

@@ -182,10 +182,11 @@
 #define ESR_ELx_WFx_ISS_WFE	(UL(1) << 0)
 #define ESR_ELx_xVC_IMM_MASK	((UL(1) << 16) - 1)
 
-/* ISS definitions for LD64B/ST64B/PSBCSYNC instructions */
+/* ISS definitions for LD64B/ST64B/{T,P}SBCSYNC instructions */
 #define ESR_ELx_ISS_OTHER_ST64BV	(0)
 #define ESR_ELx_ISS_OTHER_ST64BV0	(1)
 #define ESR_ELx_ISS_OTHER_LDST64B	(2)
+#define ESR_ELx_ISS_OTHER_TSBCSYNC	(3)
 #define ESR_ELx_ISS_OTHER_PSBCSYNC	(4)
 
 #define DISR_EL1_IDS		(UL(1) << 24)

arch/arm64/kvm/emulate-nested.c

@@ -2044,6 +2044,7 @@ static const union trap_config non_0x18_fgt[] __initconst = {
 	FGT(HFGITR, SVC_EL1, 1),
 	FGT(HFGITR, SVC_EL0, 1),
 	FGT(HFGITR, ERET, 1),
+	FGT(HFGITR2, TSBCSYNC, 1),
 };
 
 static union trap_config get_trap_config(u32 sysreg)

arch/arm64/kvm/handle_exit.c

@@ -347,6 +347,11 @@ static int handle_other(struct kvm_vcpu *vcpu)
 		if (is_l2)
 			fwd = !(hcrx & HCRX_EL2_EnALS);
 		break;
+	case ESR_ELx_ISS_OTHER_TSBCSYNC:
+		allowed = kvm_has_feat(kvm, ID_AA64DFR0_EL1, TraceBuffer, TRBE_V1P1);
+		if (is_l2)
+			fwd = (__vcpu_sys_reg(vcpu, HFGITR2_EL2) & HFGITR2_EL2_TSBCSYNC);
+		break;
 	case ESR_ELx_ISS_OTHER_PSBCSYNC:
 		allowed = kvm_has_feat(kvm, ID_AA64DFR0_EL1, PMSVer, V1P5);
 		if (is_l2)