KVM: arm64: nv: Add EL2_REG_VNCR()/EL2_REG_REDIR() sysreg helpers

Add two helpers to deal with EL2 registers are are either redirected
to the VNCR page, or that are redirected to their EL1 counterpart.

In either cases, no trap is expected.

THe relevant register descriptors are repainted accordingly.

Reviewed-by: Oliver Upton <oliver.upton@linux.dev>
Signed-off-by: Marc Zyngier <maz@kernel.org>

Author: Marc Zyngier

arch/arm64/kvm/sys_regs.c

@@ -1890,6 +1890,32 @@ static unsigned int el2_visibility(const struct kvm_vcpu *vcpu,
 	return REG_HIDDEN;
 }
 
+static bool bad_vncr_trap(struct kvm_vcpu *vcpu,
+			  struct sys_reg_params *p,
+			  const struct sys_reg_desc *r)
+{
+	/*
+	 * We really shouldn't be here, and this is likely the result
+	 * of a misconfigured trap, as this register should target the
+	 * VNCR page, and nothing else.
+	 */
+	return bad_trap(vcpu, p, r,
+			"trap of VNCR-backed register");
+}
+
+static bool bad_redir_trap(struct kvm_vcpu *vcpu,
+			   struct sys_reg_params *p,
+			   const struct sys_reg_desc *r)
+{
+	/*
+	 * We really shouldn't be here, and this is likely the result
+	 * of a misconfigured trap, as this register should target the
+	 * corresponding EL1, and nothing else.
+	 */
+	return bad_trap(vcpu, p, r,
+			"trap of EL2 register redirected to EL1");
+}
+
 #define EL2_REG(name, acc, rst, v) {		\
 	SYS_DESC(SYS_##name),			\
 	.access = acc,				\
@@ -1899,6 +1925,9 @@ static unsigned int el2_visibility(const struct kvm_vcpu *vcpu,
 	.val = v,				\
 }
 
+#define EL2_REG_VNCR(name, rst, v)	EL2_REG(name, bad_vncr_trap, rst, v)
+#define EL2_REG_REDIR(name, rst, v)	EL2_REG(name, bad_redir_trap, rst, v)
+
 /*
  * EL{0,1}2 registers are the EL2 view on an EL0 or EL1 register when
  * HCR_EL2.E2H==1, and only in the sysreg table for convenience of
@@ -2513,32 +2542,32 @@ static const struct sys_reg_desc sys_reg_descs[] = {
 	{ PMU_SYS_REG(PMCCFILTR_EL0), .access = access_pmu_evtyper,
 	  .reset = reset_val, .reg = PMCCFILTR_EL0, .val = 0 },
 
-	EL2_REG(VPIDR_EL2, access_rw, reset_unknown, 0),
-	EL2_REG(VMPIDR_EL2, access_rw, reset_unknown, 0),
+	EL2_REG_VNCR(VPIDR_EL2, reset_unknown, 0),
+	EL2_REG_VNCR(VMPIDR_EL2, reset_unknown, 0),
 	EL2_REG(SCTLR_EL2, access_rw, reset_val, SCTLR_EL2_RES1),
 	EL2_REG(ACTLR_EL2, access_rw, reset_val, 0),
-	EL2_REG(HCR_EL2, access_rw, reset_val, 0),
+	EL2_REG_VNCR(HCR_EL2, reset_val, 0),
 	EL2_REG(MDCR_EL2, access_rw, reset_val, 0),
 	EL2_REG(CPTR_EL2, access_rw, reset_val, CPTR_NVHE_EL2_RES1),
-	EL2_REG(HSTR_EL2, access_rw, reset_val, 0),
-	EL2_REG(HFGRTR_EL2, access_rw, reset_val, 0),
-	EL2_REG(HFGWTR_EL2, access_rw, reset_val, 0),
-	EL2_REG(HFGITR_EL2, access_rw, reset_val, 0),
-	EL2_REG(HACR_EL2, access_rw, reset_val, 0),
+	EL2_REG_VNCR(HSTR_EL2, reset_val, 0),
+	EL2_REG_VNCR(HFGRTR_EL2, reset_val, 0),
+	EL2_REG_VNCR(HFGWTR_EL2, reset_val, 0),
+	EL2_REG_VNCR(HFGITR_EL2, reset_val, 0),
+	EL2_REG_VNCR(HACR_EL2, reset_val, 0),
 
-	EL2_REG(HCRX_EL2, access_rw, reset_val, 0),
+	EL2_REG_VNCR(HCRX_EL2, reset_val, 0),
 
 	EL2_REG(TTBR0_EL2, access_rw, reset_val, 0),
 	EL2_REG(TTBR1_EL2, access_rw, reset_val, 0),
 	EL2_REG(TCR_EL2, access_rw, reset_val, TCR_EL2_RES1),
-	EL2_REG(VTTBR_EL2, access_rw, reset_val, 0),
-	EL2_REG(VTCR_EL2, access_rw, reset_val, 0),
+	EL2_REG_VNCR(VTTBR_EL2, reset_val, 0),
+	EL2_REG_VNCR(VTCR_EL2, reset_val, 0),
 
 	{ SYS_DESC(SYS_DACR32_EL2), trap_undef, reset_unknown, DACR32_EL2 },
-	EL2_REG(HDFGRTR_EL2, access_rw, reset_val, 0),
-	EL2_REG(HDFGWTR_EL2, access_rw, reset_val, 0),
-	EL2_REG(SPSR_EL2, access_rw, reset_val, 0),
-	EL2_REG(ELR_EL2, access_rw, reset_val, 0),
+	EL2_REG_VNCR(HDFGRTR_EL2, reset_val, 0),
+	EL2_REG_VNCR(HDFGWTR_EL2, reset_val, 0),
+	EL2_REG_REDIR(SPSR_EL2, reset_val, 0),
+	EL2_REG_REDIR(ELR_EL2, reset_val, 0),
 	{ SYS_DESC(SYS_SP_EL1), access_sp_el1},
 
 	/* AArch32 SPSR_* are RES0 if trapped from a NV guest */
@@ -2554,10 +2583,10 @@ static const struct sys_reg_desc sys_reg_descs[] = {
 	{ SYS_DESC(SYS_IFSR32_EL2), trap_undef, reset_unknown, IFSR32_EL2 },
 	EL2_REG(AFSR0_EL2, access_rw, reset_val, 0),
 	EL2_REG(AFSR1_EL2, access_rw, reset_val, 0),
-	EL2_REG(ESR_EL2, access_rw, reset_val, 0),
+	EL2_REG_REDIR(ESR_EL2, reset_val, 0),
 	{ SYS_DESC(SYS_FPEXC32_EL2), trap_undef, reset_val, FPEXC32_EL2, 0x700 },
 
-	EL2_REG(FAR_EL2, access_rw, reset_val, 0),
+	EL2_REG_REDIR(FAR_EL2, reset_val, 0),
 	EL2_REG(HPFAR_EL2, access_rw, reset_val, 0),
 
 	EL2_REG(MAIR_EL2, access_rw, reset_val, 0),
@@ -2570,7 +2599,7 @@ static const struct sys_reg_desc sys_reg_descs[] = {
 	EL2_REG(CONTEXTIDR_EL2, access_rw, reset_val, 0),
 	EL2_REG(TPIDR_EL2, access_rw, reset_val, 0),
 
-	EL2_REG(CNTVOFF_EL2, access_rw, reset_val, 0),
+	EL2_REG_VNCR(CNTVOFF_EL2, reset_val, 0),
 	EL2_REG(CNTHCTL_EL2, access_rw, reset_val, 0),
 
 	EL12_REG(CNTKCTL, access_rw, reset_val, 0),