KVM: arm64: Always set HCR_TID2

Always set HCR_TID2 to trap CTR_EL0, CCSIDR2_EL1, CLIDR_EL1, and
CSSELR_EL1. This saves a few lines of code and allows to employ their
access trap handlers for more purposes anticipated by the old
condition for setting HCR_TID2.
Suggested-by: Marc Zyngier <maz@kernel.org>
Signed-off-by: Akihiko Odaki <akihiko.odaki@daynix.com>
Reviewed-by: Reiji Watanabe <reijiw@google.com>
Link: https://lore.kernel.org/r/20230112023852.42012-6-akihiko.odaki@daynix.comSigned-off-by: Oliver Upton <oliver.upton@linux.dev>

arch/arm64/include/asm/kvm_arm.h

@@ -81,11 +81,12 @@
  * SWIO:	Turn set/way invalidates into set/way clean+invalidate
  * PTW:		Take a stage2 fault if a stage1 walk steps in device memory
  * TID3:	Trap EL1 reads of group 3 ID registers
+ * TID2:	Trap CTR_EL0, CCSIDR2_EL1, CLIDR_EL1, and CSSELR_EL1
  */
 #define HCR_GUEST_FLAGS (HCR_TSC | HCR_TSW | HCR_TWE | HCR_TWI | HCR_VM | \
 			 HCR_BSU_IS | HCR_FB | HCR_TACR | \
 			 HCR_AMO | HCR_SWIO | HCR_TIDCP | HCR_RW | HCR_TLOR | \
-			 HCR_FMO | HCR_IMO | HCR_PTW | HCR_TID3 )
+			 HCR_FMO | HCR_IMO | HCR_PTW | HCR_TID3 | HCR_TID2)
 #define HCR_VIRT_EXCP_MASK (HCR_VSE | HCR_VI | HCR_VF)
 #define HCR_HOST_NVHE_FLAGS (HCR_RW | HCR_API | HCR_APK | HCR_ATA)
 #define HCR_HOST_NVHE_PROTECTED_FLAGS (HCR_HOST_NVHE_FLAGS | HCR_TSC)

arch/arm64/include/asm/kvm_emulate.h

@@ -88,10 +88,6 @@ static inline void vcpu_reset_hcr(struct kvm_vcpu *vcpu)
 	if (vcpu_el1_is_32bit(vcpu))
 		vcpu->arch.hcr_el2 &= ~HCR_RW;
 
-	if (cpus_have_const_cap(ARM64_MISMATCHED_CACHE_TYPE) ||
-	    vcpu_el1_is_32bit(vcpu))
-		vcpu->arch.hcr_el2 |= HCR_TID2;
-
 	if (kvm_has_mte(vcpu->kvm))
 		vcpu->arch.hcr_el2 |= HCR_ATA;
 }

arch/arm64/include/asm/kvm_host.h

@@ -705,7 +705,6 @@ static inline bool __vcpu_read_sys_reg_from_cpu(int reg, u64 *val)
 		return false;
 
 	switch (reg) {
-	case CSSELR_EL1:	*val = read_sysreg_s(SYS_CSSELR_EL1);	break;
 	case SCTLR_EL1:		*val = read_sysreg_s(SYS_SCTLR_EL12);	break;
 	case CPACR_EL1:		*val = read_sysreg_s(SYS_CPACR_EL12);	break;
 	case TTBR0_EL1:		*val = read_sysreg_s(SYS_TTBR0_EL12);	break;
@@ -750,7 +749,6 @@ static inline bool __vcpu_write_sys_reg_to_cpu(u64 val, int reg)
 		return false;
 
 	switch (reg) {
-	case CSSELR_EL1:	write_sysreg_s(val, SYS_CSSELR_EL1);	break;
 	case SCTLR_EL1:		write_sysreg_s(val, SYS_SCTLR_EL12);	break;
 	case CPACR_EL1:		write_sysreg_s(val, SYS_CPACR_EL12);	break;
 	case TTBR0_EL1:		write_sysreg_s(val, SYS_TTBR0_EL12);	break;

arch/arm64/kvm/hyp/include/hyp/sysreg-sr.h

@@ -39,7 +39,6 @@ static inline bool ctxt_has_mte(struct kvm_cpu_context *ctxt)
 
 static inline void __sysreg_save_el1_state(struct kvm_cpu_context *ctxt)
 {
-	ctxt_sys_reg(ctxt, CSSELR_EL1)	= read_sysreg(csselr_el1);
 	ctxt_sys_reg(ctxt, SCTLR_EL1)	= read_sysreg_el1(SYS_SCTLR);
 	ctxt_sys_reg(ctxt, CPACR_EL1)	= read_sysreg_el1(SYS_CPACR);
 	ctxt_sys_reg(ctxt, TTBR0_EL1)	= read_sysreg_el1(SYS_TTBR0);
@@ -95,7 +94,6 @@ static inline void __sysreg_restore_user_state(struct kvm_cpu_context *ctxt)
 static inline void __sysreg_restore_el1_state(struct kvm_cpu_context *ctxt)
 {
 	write_sysreg(ctxt_sys_reg(ctxt, MPIDR_EL1),	vmpidr_el2);
-	write_sysreg(ctxt_sys_reg(ctxt, CSSELR_EL1),	csselr_el1);
 
 	if (has_vhe() ||
 	    !cpus_have_final_cap(ARM64_WORKAROUND_SPECULATIVE_AT)) {