[PATCH v11 22/43] KVM: arm64: nv: Set a handler for the system instruction traps

[Marc Zyngier]

When HCR.NV bit is set, execution of the EL2 translation regime address
aranslation instructions and TLB maintenance instructions are trapped to
EL2. In addition, execution of the EL1 translation regime address
aranslation instructions and TLB maintenance instructions that are only
accessible from EL2 and above are trapped to EL2. In these cases,
ESR_EL2.EC will be set to 0x18.

Rework the system instruction emulation framework to handle potentially
all system instruction traps other than MSR/MRS instructions. Those
system instructions would be AT and TLBI instructions controlled by
HCR_EL2.NV, AT, and TTLB bits.

Signed-off-by: Jintack Lim <jintack.lim at linaro.org>
[maz: squashed two patches together, redispatched various bits around]
Signed-off-by: Marc Zyngier <maz at kernel.org>
---
 arch/arm64/kvm/sys_regs.c | 59 +++++++++++++++++++++++++++++----------
 1 file changed, 44 insertions(+), 15 deletions(-)

diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
index f42f3ed3724c..49d00f0cdda0 100644
--- a/arch/arm64/kvm/sys_regs.c
+++ b/arch/arm64/kvm/sys_regs.c
@@ -2246,16 +2246,6 @@ static u64 reset_hcr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r)
  * guest...
  */
 static const struct sys_reg_desc sys_reg_descs[] = {
-	{ SYS_DESC(SYS_DC_ISW), access_dcsw },
-	{ SYS_DESC(SYS_DC_IGSW), access_dcgsw },
-	{ SYS_DESC(SYS_DC_IGDSW), access_dcgsw },
-	{ SYS_DESC(SYS_DC_CSW), access_dcsw },
-	{ SYS_DESC(SYS_DC_CGSW), access_dcgsw },
-	{ SYS_DESC(SYS_DC_CGDSW), access_dcgsw },
-	{ SYS_DESC(SYS_DC_CISW), access_dcsw },
-	{ SYS_DESC(SYS_DC_CIGSW), access_dcgsw },
-	{ SYS_DESC(SYS_DC_CIGDSW), access_dcgsw },
-
 	DBG_BCR_BVR_WCR_WVR_EL1(0),
 	DBG_BCR_BVR_WCR_WVR_EL1(1),
 	{ SYS_DESC(SYS_MDCCINT_EL1), trap_debug_regs, reset_val, MDCCINT_EL1, 0 },
@@ -2786,6 +2776,18 @@ static const struct sys_reg_desc sys_reg_descs[] = {
 	EL2_REG(SP_EL2, NULL, reset_unknown, 0),
 };
 
+static struct sys_reg_desc sys_insn_descs[] = {
+	{ SYS_DESC(SYS_DC_ISW), access_dcsw },
+	{ SYS_DESC(SYS_DC_IGSW), access_dcgsw },
+	{ SYS_DESC(SYS_DC_IGDSW), access_dcgsw },
+	{ SYS_DESC(SYS_DC_CSW), access_dcsw },
+	{ SYS_DESC(SYS_DC_CGSW), access_dcgsw },
+	{ SYS_DESC(SYS_DC_CGDSW), access_dcgsw },
+	{ SYS_DESC(SYS_DC_CISW), access_dcsw },
+	{ SYS_DESC(SYS_DC_CIGSW), access_dcgsw },
+	{ SYS_DESC(SYS_DC_CIGDSW), access_dcgsw },
+};
+
 static const struct sys_reg_desc *first_idreg;
 
 static bool trap_dbgdidr(struct kvm_vcpu *vcpu,
@@ -3479,6 +3481,24 @@ static bool emulate_sys_reg(struct kvm_vcpu *vcpu,
 	return false;
 }
 
+static int emulate_sys_instr(struct kvm_vcpu *vcpu, struct sys_reg_params *p)
+{
+	const struct sys_reg_desc *r;
+
+	/* Search from the system instruction table. */
+	r = find_reg(p, sys_insn_descs, ARRAY_SIZE(sys_insn_descs));
+
+	if (likely(r)) {
+		perform_access(vcpu, p, r);
+	} else {
+		kvm_err("Unsupported guest sys instruction at: %lx\n",
+			*vcpu_pc(vcpu));
+		print_sys_reg_instr(p);
+		kvm_inject_undefined(vcpu);
+	}
+	return 1;
+}
+
 static void kvm_reset_id_regs(struct kvm_vcpu *vcpu)
 {
 	const struct sys_reg_desc *idreg = first_idreg;
@@ -3526,7 +3546,8 @@ void kvm_reset_sys_regs(struct kvm_vcpu *vcpu)
 }
 
 /**
- * kvm_handle_sys_reg -- handles a mrs/msr trap on a guest sys_reg access
+ * kvm_handle_sys_reg -- handles a system instruction or mrs/msr instruction
+ *			 trap on a guest execution
  * @vcpu: The VCPU pointer
  */
 int kvm_handle_sys_reg(struct kvm_vcpu *vcpu)
@@ -3543,12 +3564,19 @@ int kvm_handle_sys_reg(struct kvm_vcpu *vcpu)
 	params = esr_sys64_to_params(esr);
 	params.regval = vcpu_get_reg(vcpu, Rt);
 
-	if (!emulate_sys_reg(vcpu, &params))
+	/* System register? */
+	if (params.Op0 == 2 || params.Op0 == 3) {
+		if (!emulate_sys_reg(vcpu, &params))
+			return 1;
+
+		if (!params.is_write)
+			vcpu_set_reg(vcpu, Rt, params.regval);
+
 		return 1;
+	}
 
-	if (!params.is_write)
-		vcpu_set_reg(vcpu, Rt, params.regval);
-	return 1;
+	/* Hints, PSTATE (Op0 == 0) and System instructions (Op0 == 1) */
+	return emulate_sys_instr(vcpu, &params);
 }
 
 /******************************************************************************
@@ -4002,6 +4030,7 @@ int __init kvm_sys_reg_table_init(void)
 	valid &= check_sysreg_table(cp15_regs, ARRAY_SIZE(cp15_regs), true);
 	valid &= check_sysreg_table(cp15_64_regs, ARRAY_SIZE(cp15_64_regs), true);
 	valid &= check_sysreg_table(invariant_sys_regs, ARRAY_SIZE(invariant_sys_regs), false);
+	valid &= check_sysreg_table(sys_insn_descs, ARRAY_SIZE(sys_insn_descs), false);
 
 	if (!valid)
 		return -EINVAL;
-- 
2.39.2