KVM: arm64: Handle PSB CSYNC traps

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

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 instructions */
+/* ISS definitions for LD64B/ST64B/PSBCSYNC 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_PSBCSYNC	(4)
 
 #define DISR_EL1_IDS		(UL(1) << 24)
 /*

arch/arm64/kvm/emulate-nested.c

@@ -2000,6 +2000,7 @@ static const struct encoding_to_trap_config encoding_to_fgt[] __initconst = {
  * trap is handled somewhere else.
  */
 static const union trap_config non_0x18_fgt[] __initconst = {
+	FGT(HFGITR, PSBCSYNC, 1),
 	FGT(HFGITR, nGCSSTR_EL1, 0),
 	FGT(HFGITR, SVC_EL1, 1),
 	FGT(HFGITR, SVC_EL0, 1),

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_PSBCSYNC:
+		allowed = kvm_has_feat(kvm, ID_AA64DFR0_EL1, PMSVer, V1P5);
+		if (is_l2)
+			fwd = (__vcpu_sys_reg(vcpu, HFGITR_EL2) & HFGITR_EL2_PSBCSYNC);
+		break;
 	default:
 		/* Clearly, we're missing something. */
 		WARN_ON_ONCE(1);

arch/arm64/tools/sysreg

@@ -3406,7 +3406,7 @@ Field	0	AFSR0_EL1
 EndSysreg
 
 Sysreg HFGITR_EL2	3	4	1	1	6
-Res0	63
+Field   63	PSBCSYNC
 Field	62	ATS1E1A
 Res0	61
 Field	60	COSPRCTX