KVM: arm64: nv: Move system instructions to their own sys_reg_desc array

As NV results in a bunch of system instructions being trapped, it makes
sense to pull the system instructions into their own little array, where
they will eventually be joined by AT, TLBI and a bunch of other CMOs.

Based on an initial patch by Jintack Lim.

Reviewed-by: Joey Gouly <joey.gouly@arm.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20240214131827.2856277-13-maz@kernel.org
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>

diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
index 3c31f8cb9eefac3dfba620a6070ecb807d394515..70043bd78cd447d25348d377b8801e233220042a 100644 (file)
--- a/arch/arm64/kvm/sys_regs.c
+++ b/arch/arm64/kvm/sys_regs.c
@@ -2196,16 +2196,6 @@ 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 },
@@ -2737,6 +2727,18 @@ 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,
@@ -3429,6 +3431,24 @@ 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;
@@ -3476,7 +3496,8 @@ 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)
@@ -3493,12 +3514,19 @@ 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 registers have Op0=={2,3}, as per DDI487 J.a C5.1.2 */
+       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);
 }
 
 /******************************************************************************
@@ -3952,6 +3980,7 @@ 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;