@@ -683,6 +683,7 @@ int kvm_handle_cp14_64(struct kvm_vcpu *vcpu);
int kvm_handle_cp15_32(struct kvm_vcpu *vcpu);
int kvm_handle_cp15_64(struct kvm_vcpu *vcpu);
int kvm_handle_sys_reg(struct kvm_vcpu *vcpu);
+int kvm_handle_cp10_id(struct kvm_vcpu *vcpu);
void kvm_reset_sys_regs(struct kvm_vcpu *vcpu);
@@ -167,6 +167,7 @@ static exit_handle_fn arm_exit_handlers[] = {
[ESR_ELx_EC_CP15_64] = kvm_handle_cp15_64,
[ESR_ELx_EC_CP14_MR] = kvm_handle_cp14_32,
[ESR_ELx_EC_CP14_LS] = kvm_handle_cp14_load_store,
+ [ESR_ELx_EC_CP10_ID] = kvm_handle_cp10_id,
[ESR_ELx_EC_CP14_64] = kvm_handle_cp14_64,
[ESR_ELx_EC_HVC32] = handle_hvc,
[ESR_ELx_EC_SMC32] = handle_smc,
@@ -2346,6 +2346,77 @@ static int kvm_handle_cp_64(struct kvm_vcpu *vcpu,
static bool emulate_sys_reg(struct kvm_vcpu *vcpu, struct sys_reg_params *params);
+/*
+ * The CP10 ID registers are architecturally mapped to AArch64 feature
+ * registers. Abuse that fact so we can rely on the AArch64 handler for accesses
+ * from AArch32.
+ */
+static bool kvm_esr_cp10_id_to_sys64(u32 esr, struct sys_reg_params *params)
+{
+ u8 reg_id = (esr >> 10) & 0xf;
+ bool valid;
+
+ params->is_write = ((esr & 1) == 0);
+ params->Op0 = 3;
+ params->Op1 = 0;
+ params->CRn = 0;
+ params->CRm = 3;
+
+ /* CP10 ID registers are read-only */
+ valid = !params->is_write;
+
+ switch (reg_id) {
+ /* MVFR0 */
+ case 0b0111:
+ params->Op2 = 0;
+ break;
+ /* MVFR1 */
+ case 0b0110:
+ params->Op2 = 1;
+ break;
+ /* MVFR2 */
+ case 0b0101:
+ params->Op2 = 2;
+ break;
+ default:
+ valid = false;
+ }
+
+ if (valid)
+ return true;
+
+ kvm_pr_unimpl("Unhandled cp10 register %s: %u\n",
+ params->is_write ? "write" : "read", reg_id);
+ return false;
+}
+
+/**
+ * kvm_handle_cp10_id() - Handles a VMRS trap on guest access to a 'Media and
+ * VFP Register' from AArch32.
+ * @vcpu: The vCPU pointer
+ *
+ * MVFR{0-2} are architecturally mapped to the AArch64 MVFR{0-2}_EL1 registers.
+ * Work out the correct AArch64 system register encoding and reroute to the
+ * AArch64 system register emulation.
+ */
+int kvm_handle_cp10_id(struct kvm_vcpu *vcpu)
+{
+ int Rt = kvm_vcpu_sys_get_rt(vcpu);
+ u32 esr = kvm_vcpu_get_esr(vcpu);
+ struct sys_reg_params params;
+
+ /* UNDEF on any unhandled register access */
+ if (!kvm_esr_cp10_id_to_sys64(esr, ¶ms)) {
+ kvm_inject_undefined(vcpu);
+ return 1;
+ }
+
+ if (emulate_sys_reg(vcpu, ¶ms))
+ vcpu_set_reg(vcpu, Rt, params.regval);
+
+ return 1;
+}
+
/**
* kvm_emulate_cp15_id_reg() - Handles an MRC trap on a guest CP15 access where
* CRn=0, which corresponds to the AArch32 feature
In order to enable HCR_EL2.TID3 for AArch32 guests KVM needs to handle traps where ESR_EL2.EC=0x8, which corresponds to an attempted VMRS access from an ID group register. Specifically, the MVFR{0-2} registers are accessed this way from AArch32. Conveniently, these registers are architecturally mapped to MVFR{0-2}_EL1 in AArch64. Furthermore, KVM already handles reads to these aliases in AArch64. Plumb VMRS read traps through to the general AArch64 system register handler. Signed-off-by: Oliver Upton <oupton@google.com> Reviewed-by: Reiji Watanabe <reijiw@google.com> --- arch/arm64/include/asm/kvm_host.h | 1 + arch/arm64/kvm/handle_exit.c | 1 + arch/arm64/kvm/sys_regs.c | 71 +++++++++++++++++++++++++++++++ 3 files changed, 73 insertions(+)