[PATCH v6 03/12] KVM: arm64: Move early handlers to per-EC handlers
Fuad Tabba
tabba at google.com
Wed Sep 22 05:46:55 PDT 2021
From: Marc Zyngier <maz at kernel.org>
Simplify the early exception handling by slicing the gigantic decoding
tree into a more manageable set of functions, similar to what we have
in handle_exit.c.
This will also make the structure reusable for pKVM's own early exit
handling.
Signed-off-by: Marc Zyngier <maz at kernel.org>
Signed-off-by: Fuad Tabba <tabba at google.com>
---
arch/arm64/kvm/hyp/include/hyp/switch.h | 160 ++++++++++++++----------
arch/arm64/kvm/hyp/nvhe/switch.c | 17 +++
arch/arm64/kvm/hyp/vhe/switch.c | 17 +++
3 files changed, 126 insertions(+), 68 deletions(-)
diff --git a/arch/arm64/kvm/hyp/include/hyp/switch.h b/arch/arm64/kvm/hyp/include/hyp/switch.h
index 54abc8298ec3..0397606c0951 100644
--- a/arch/arm64/kvm/hyp/include/hyp/switch.h
+++ b/arch/arm64/kvm/hyp/include/hyp/switch.h
@@ -136,16 +136,7 @@ static inline void ___deactivate_traps(struct kvm_vcpu *vcpu)
static inline bool __populate_fault_info(struct kvm_vcpu *vcpu)
{
- u8 ec;
- u64 esr;
-
- esr = vcpu->arch.fault.esr_el2;
- ec = ESR_ELx_EC(esr);
-
- if (ec != ESR_ELx_EC_DABT_LOW && ec != ESR_ELx_EC_IABT_LOW)
- return true;
-
- return __get_fault_info(esr, &vcpu->arch.fault);
+ return __get_fault_info(vcpu->arch.fault.esr_el2, &vcpu->arch.fault);
}
static inline void __hyp_sve_save_host(struct kvm_vcpu *vcpu)
@@ -166,8 +157,13 @@ static inline void __hyp_sve_restore_guest(struct kvm_vcpu *vcpu)
write_sysreg_el1(__vcpu_sys_reg(vcpu, ZCR_EL1), SYS_ZCR);
}
-/* Check for an FPSIMD/SVE trap and handle as appropriate */
-static inline bool __hyp_handle_fpsimd(struct kvm_vcpu *vcpu)
+/*
+ * We trap the first access to the FP/SIMD to save the host context and
+ * restore the guest context lazily.
+ * If FP/SIMD is not implemented, handle the trap and inject an undefined
+ * instruction exception to the guest. Similarly for trapped SVE accesses.
+ */
+static bool kvm_hyp_handle_fpsimd(struct kvm_vcpu *vcpu, u64 *exit_code)
{
bool sve_guest, sve_host;
u8 esr_ec;
@@ -185,9 +181,6 @@ static inline bool __hyp_handle_fpsimd(struct kvm_vcpu *vcpu)
}
esr_ec = kvm_vcpu_trap_get_class(vcpu);
- if (esr_ec != ESR_ELx_EC_FP_ASIMD &&
- esr_ec != ESR_ELx_EC_SVE)
- return false;
/* Don't handle SVE traps for non-SVE vcpus here: */
if (!sve_guest && esr_ec != ESR_ELx_EC_FP_ASIMD)
@@ -325,7 +318,7 @@ static inline bool esr_is_ptrauth_trap(u32 esr)
DECLARE_PER_CPU(struct kvm_cpu_context, kvm_hyp_ctxt);
-static inline bool __hyp_handle_ptrauth(struct kvm_vcpu *vcpu)
+static bool kvm_hyp_handle_ptrauth(struct kvm_vcpu *vcpu, u64 *exit_code)
{
struct kvm_cpu_context *ctxt;
u64 val;
@@ -350,6 +343,87 @@ static inline bool __hyp_handle_ptrauth(struct kvm_vcpu *vcpu)
return true;
}
+static bool kvm_hyp_handle_sysreg(struct kvm_vcpu *vcpu, u64 *exit_code)
+{
+ if (cpus_have_final_cap(ARM64_WORKAROUND_CAVIUM_TX2_219_TVM) &&
+ handle_tx2_tvm(vcpu))
+ return true;
+
+ if (static_branch_unlikely(&vgic_v3_cpuif_trap) &&
+ __vgic_v3_perform_cpuif_access(vcpu) == 1)
+ return true;
+
+ return false;
+}
+
+static bool kvm_hyp_handle_cp15(struct kvm_vcpu *vcpu, u64 *exit_code)
+{
+ if (static_branch_unlikely(&vgic_v3_cpuif_trap) &&
+ __vgic_v3_perform_cpuif_access(vcpu) == 1)
+ return true;
+
+ return false;
+}
+
+static bool kvm_hyp_handle_iabt_low(struct kvm_vcpu *vcpu, u64 *exit_code)
+{
+ if (!__populate_fault_info(vcpu))
+ return true;
+
+ return false;
+}
+
+static bool kvm_hyp_handle_dabt_low(struct kvm_vcpu *vcpu, u64 *exit_code)
+{
+ if (!__populate_fault_info(vcpu))
+ return true;
+
+ if (static_branch_unlikely(&vgic_v2_cpuif_trap)) {
+ bool valid;
+
+ valid = kvm_vcpu_trap_get_fault_type(vcpu) == FSC_FAULT &&
+ kvm_vcpu_dabt_isvalid(vcpu) &&
+ !kvm_vcpu_abt_issea(vcpu) &&
+ !kvm_vcpu_abt_iss1tw(vcpu);
+
+ if (valid) {
+ int ret = __vgic_v2_perform_cpuif_access(vcpu);
+
+ if (ret == 1)
+ return true;
+
+ /* Promote an illegal access to an SError.*/
+ if (ret == -1)
+ *exit_code = ARM_EXCEPTION_EL1_SERROR;
+ }
+ }
+
+ return false;
+}
+
+typedef bool (*exit_handler_fn)(struct kvm_vcpu *, u64 *);
+
+static const exit_handler_fn *kvm_get_exit_handler_array(void);
+
+/*
+ * Allow the hypervisor to handle the exit with an exit handler if it has one.
+ *
+ * Returns true if the hypervisor handled the exit, and control should go back
+ * to the guest, or false if it hasn't.
+ */
+static inline bool kvm_hyp_handle_exit(struct kvm_vcpu *vcpu, u64 *exit_code)
+{
+ const exit_handler_fn *handlers = kvm_get_exit_handler_array();
+ exit_handler_fn fn;
+
+ fn = handlers[kvm_vcpu_trap_get_class(vcpu)];
+
+ if (fn)
+ return fn(vcpu, exit_code);
+
+ return false;
+}
+
/*
* Return true when we were able to fixup the guest exit and should return to
* the guest, false when we should restore the host state and return to the
@@ -384,59 +458,9 @@ static inline bool fixup_guest_exit(struct kvm_vcpu *vcpu, u64 *exit_code)
if (*exit_code != ARM_EXCEPTION_TRAP)
goto exit;
- if (cpus_have_final_cap(ARM64_WORKAROUND_CAVIUM_TX2_219_TVM) &&
- kvm_vcpu_trap_get_class(vcpu) == ESR_ELx_EC_SYS64 &&
- handle_tx2_tvm(vcpu))
+ /* Check if there's an exit handler and allow it to handle the exit. */
+ if (kvm_hyp_handle_exit(vcpu, exit_code))
goto guest;
-
- /*
- * We trap the first access to the FP/SIMD to save the host context
- * and restore the guest context lazily.
- * If FP/SIMD is not implemented, handle the trap and inject an
- * undefined instruction exception to the guest.
- * Similarly for trapped SVE accesses.
- */
- if (__hyp_handle_fpsimd(vcpu))
- goto guest;
-
- if (__hyp_handle_ptrauth(vcpu))
- goto guest;
-
- if (!__populate_fault_info(vcpu))
- goto guest;
-
- if (static_branch_unlikely(&vgic_v2_cpuif_trap)) {
- bool valid;
-
- valid = kvm_vcpu_trap_get_class(vcpu) == ESR_ELx_EC_DABT_LOW &&
- kvm_vcpu_trap_get_fault_type(vcpu) == FSC_FAULT &&
- kvm_vcpu_dabt_isvalid(vcpu) &&
- !kvm_vcpu_abt_issea(vcpu) &&
- !kvm_vcpu_abt_iss1tw(vcpu);
-
- if (valid) {
- int ret = __vgic_v2_perform_cpuif_access(vcpu);
-
- if (ret == 1)
- goto guest;
-
- /* Promote an illegal access to an SError.*/
- if (ret == -1)
- *exit_code = ARM_EXCEPTION_EL1_SERROR;
-
- goto exit;
- }
- }
-
- if (static_branch_unlikely(&vgic_v3_cpuif_trap) &&
- (kvm_vcpu_trap_get_class(vcpu) == ESR_ELx_EC_SYS64 ||
- kvm_vcpu_trap_get_class(vcpu) == ESR_ELx_EC_CP15_32)) {
- int ret = __vgic_v3_perform_cpuif_access(vcpu);
-
- if (ret == 1)
- goto guest;
- }
-
exit:
/* Return to the host kernel and handle the exit */
return false;
diff --git a/arch/arm64/kvm/hyp/nvhe/switch.c b/arch/arm64/kvm/hyp/nvhe/switch.c
index a34b01cc8ab9..c52d580708e0 100644
--- a/arch/arm64/kvm/hyp/nvhe/switch.c
+++ b/arch/arm64/kvm/hyp/nvhe/switch.c
@@ -158,6 +158,23 @@ static void __pmu_switch_to_host(struct kvm_cpu_context *host_ctxt)
write_sysreg(pmu->events_host, pmcntenset_el0);
}
+static const exit_handler_fn hyp_exit_handlers[] = {
+ [0 ... ESR_ELx_EC_MAX] = NULL,
+ [ESR_ELx_EC_CP15_32] = kvm_hyp_handle_cp15,
+ [ESR_ELx_EC_CP15_64] = kvm_hyp_handle_cp15,
+ [ESR_ELx_EC_SYS64] = kvm_hyp_handle_sysreg,
+ [ESR_ELx_EC_SVE] = kvm_hyp_handle_fpsimd,
+ [ESR_ELx_EC_FP_ASIMD] = kvm_hyp_handle_fpsimd,
+ [ESR_ELx_EC_IABT_LOW] = kvm_hyp_handle_iabt_low,
+ [ESR_ELx_EC_DABT_LOW] = kvm_hyp_handle_dabt_low,
+ [ESR_ELx_EC_PAC] = kvm_hyp_handle_ptrauth,
+};
+
+static const exit_handler_fn *kvm_get_exit_handler_array(void)
+{
+ return hyp_exit_handlers;
+}
+
/* Switch to the guest for legacy non-VHE systems */
int __kvm_vcpu_run(struct kvm_vcpu *vcpu)
{
diff --git a/arch/arm64/kvm/hyp/vhe/switch.c b/arch/arm64/kvm/hyp/vhe/switch.c
index ded2c66675f0..0e0d342358f7 100644
--- a/arch/arm64/kvm/hyp/vhe/switch.c
+++ b/arch/arm64/kvm/hyp/vhe/switch.c
@@ -96,6 +96,23 @@ void deactivate_traps_vhe_put(struct kvm_vcpu *vcpu)
__deactivate_traps_common(vcpu);
}
+static const exit_handler_fn hyp_exit_handlers[] = {
+ [0 ... ESR_ELx_EC_MAX] = NULL,
+ [ESR_ELx_EC_CP15_32] = kvm_hyp_handle_cp15,
+ [ESR_ELx_EC_CP15_64] = kvm_hyp_handle_cp15,
+ [ESR_ELx_EC_SYS64] = kvm_hyp_handle_sysreg,
+ [ESR_ELx_EC_SVE] = kvm_hyp_handle_fpsimd,
+ [ESR_ELx_EC_FP_ASIMD] = kvm_hyp_handle_fpsimd,
+ [ESR_ELx_EC_IABT_LOW] = kvm_hyp_handle_iabt_low,
+ [ESR_ELx_EC_DABT_LOW] = kvm_hyp_handle_dabt_low,
+ [ESR_ELx_EC_PAC] = kvm_hyp_handle_ptrauth,
+};
+
+static const exit_handler_fn *kvm_get_exit_handler_array(void)
+{
+ return hyp_exit_handlers;
+}
+
/* Switch to the guest for VHE systems running in EL2 */
static int __kvm_vcpu_run_vhe(struct kvm_vcpu *vcpu)
{
--
2.33.0.464.g1972c5931b-goog
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