[PATCH v3 4/9] arm64: KVM: common infrastructure for handling AArch32 CP14/CP15

Marc Zyngier
2014-06-20T13:00:13Z

As we're about to trap a bunch of CP14 registers, let's rework
the CP15 handling so it can be generalized and work with multiple
tables.

Reviewed-by: Anup Patel <anup.patel@linaro.org>
Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
---
arch/arm64/include/asm/kvm_asm.h | 2 +-
arch/arm64/include/asm/kvm_coproc.h | 3 +-
arch/arm64/include/asm/kvm_host.h | 9 ++-
arch/arm64/kvm/handle_exit.c | 4 +-
arch/arm64/kvm/sys_regs.c | 133 +++++++++++++++++++++++++++++-------
5 files changed, 122 insertions(+), 29 deletions(-)

diff --git a/arch/arm64/include/asm/kvm_asm.h b/arch/arm64/include/asm/kvm_asm.h
index e6b159a..12f9dd7 100644
--- a/arch/arm64/include/asm/kvm_asm.h
+++ b/arch/arm64/include/asm/kvm_asm.h
@@ -93,7 +93,7 @@
#define c10_AMAIR0 (AMAIR_EL1 * 2) /* Aux Memory Attr Indirection Reg */
#define c10_AMAIR1 (c10_AMAIR0 + 1)/* Aux Memory Attr Indirection Reg */
#define c14_CNTKCTL (CNTKCTL_EL1 * 2) /* Timer Control Register (PL1) */
-#define NR_CP15_REGS (NR_SYS_REGS * 2)
+#define NR_COPRO_REGS (NR_SYS_REGS * 2)

#define ARM_EXCEPTION_IRQ 0
#define ARM_EXCEPTION_TRAP 1
diff --git a/arch/arm64/include/asm/kvm_coproc.h b/arch/arm64/include/asm/kvm_coproc.h
index 9a59301..0b52377 100644
--- a/arch/arm64/include/asm/kvm_coproc.h
+++ b/arch/arm64/include/asm/kvm_coproc.h
@@ -39,7 +39,8 @@ void kvm_register_target_sys_reg_table(unsigned int target,
struct kvm_sys_reg_target_table *table);

int kvm_handle_cp14_load_store(struct kvm_vcpu *vcpu, struct kvm_run *run);
-int kvm_handle_cp14_access(struct kvm_vcpu *vcpu, struct kvm_run *run);
+int kvm_handle_cp14_32(struct kvm_vcpu *vcpu, struct kvm_run *run);
+int kvm_handle_cp14_64(struct kvm_vcpu *vcpu, struct kvm_run *run);
int kvm_handle_cp15_32(struct kvm_vcpu *vcpu, struct kvm_run *run);
int kvm_handle_cp15_64(struct kvm_vcpu *vcpu, struct kvm_run *run);
int kvm_handle_sys_reg(struct kvm_vcpu *vcpu, struct kvm_run *run);
diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
index 79573c86..108a297 100644
--- a/arch/arm64/include/asm/kvm_host.h
+++ b/arch/arm64/include/asm/kvm_host.h
@@ -86,7 +86,7 @@ struct kvm_cpu_context {
struct kvm_regs gp_regs;
union {
u64 sys_regs[NR_SYS_REGS];
- u32 cp15[NR_CP15_REGS];
+ u32 copro[NR_COPRO_REGS];
};
};

@@ -141,7 +141,12 @@ struct kvm_vcpu_arch {

#define vcpu_gp_regs(v) (&(v)->arch.ctxt.gp_regs)
#define vcpu_sys_reg(v,r) ((v)->arch.ctxt.sys_regs[(r)])
-#define vcpu_cp15(v,r) ((v)->arch.ctxt.cp15[(r)])
+/*
+ * CP14 and CP15 live in the same array, as they are backed by the
+ * same system registers.
+ */
+#define vcpu_cp14(v,r) ((v)->arch.ctxt.copro[(r)])
+#define vcpu_cp15(v,r) ((v)->arch.ctxt.copro[(r)])

struct kvm_vm_stat {
u32 remote_tlb_flush;
diff --git a/arch/arm64/kvm/handle_exit.c b/arch/arm64/kvm/handle_exit.c
index 182415e..e28be51 100644
--- a/arch/arm64/kvm/handle_exit.c
+++ b/arch/arm64/kvm/handle_exit.c
@@ -73,9 +73,9 @@ static exit_handle_fn arm_exit_handlers[] = {
[ESR_EL2_EC_WFI] = kvm_handle_wfx,
[ESR_EL2_EC_CP15_32] = kvm_handle_cp15_32,
[ESR_EL2_EC_CP15_64] = kvm_handle_cp15_64,
- [ESR_EL2_EC_CP14_MR] = kvm_handle_cp14_access,
+ [ESR_EL2_EC_CP14_MR] = kvm_handle_cp14_32,
[ESR_EL2_EC_CP14_LS] = kvm_handle_cp14_load_store,
- [ESR_EL2_EC_CP14_64] = kvm_handle_cp14_access,
+ [ESR_EL2_EC_CP14_64] = kvm_handle_cp14_64,
[ESR_EL2_EC_HVC32] = handle_hvc,
[ESR_EL2_EC_SMC32] = handle_smc,
[ESR_EL2_EC_HVC64] = handle_hvc,
diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
index 808e3b2..fb6eece 100644
--- a/arch/arm64/kvm/sys_regs.c
+++ b/arch/arm64/kvm/sys_regs.c
@@ -483,6 +483,10 @@ static const struct sys_reg_desc sys_reg_descs[] = {
NULL, reset_val, FPEXC32_EL2, 0x70 },
};

+/* Trapped cp14 registers */
+static const struct sys_reg_desc cp14_regs[] = {
+};
+
/*
* Trapped cp15 registers. TTBR0/TTBR1 get a double encoding,
* depending on the way they are accessed (as a 32bit or a 64bit
@@ -590,26 +594,29 @@ int kvm_handle_cp14_load_store(struct kvm_vcpu *vcpu, struct kvm_run *run)
return 1;
}

-int kvm_handle_cp14_access(struct kvm_vcpu *vcpu, struct kvm_run *run)
-{
- kvm_inject_undefined(vcpu);
- return 1;
-}
-
-static void emulate_cp15(struct kvm_vcpu *vcpu,
- const struct sys_reg_params *params)
+/*
+ * emulate_cp -- tries to match a sys_reg access in a handling table, and
+ * call the corresponding trap handler.
+ *
+ * @params: pointer to the descriptor of the access
+ * @table: array of trap descriptors
+ * @num: size of the trap descriptor array
+ *
+ * Return 0 if the access has been handled, and -1 if not.
+ */
+static int emulate_cp(struct kvm_vcpu *vcpu,
+ const struct sys_reg_params *params,
+ const struct sys_reg_desc *table,
+ size_t num)
{
- size_t num;
- const struct sys_reg_desc *table, *r;
+ const struct sys_reg_desc *r;

- table = get_target_table(vcpu->arch.target, false, &num);
+ if (!table)
+ return -1; /* Not handled */

- /* Search target-specific then generic table. */
r = find_reg(params, table, num);
- if (!r)
- r = find_reg(params, cp15_regs, ARRAY_SIZE(cp15_regs));

- if (likely(r)) {
+ if (r) {
/*
* Not having an accessor means that we have
* configured a trap that we don't know how to
@@ -621,22 +628,51 @@ static void emulate_cp15(struct kvm_vcpu *vcpu,
if (likely(r->access(vcpu, params, r))) {
/* Skip instruction, since it was emulated */
kvm_skip_instr(vcpu, kvm_vcpu_trap_il_is32bit(vcpu));
- return;
}
- /* If access function fails, it should complain. */
+
+ /* Handled */
+ return 0;
}

- kvm_err("Unsupported guest CP15 access at: %08lx\n", *vcpu_pc(vcpu));
+ /* Not handled */
+ return -1;
+}
+
+static void unhandled_cp_access(struct kvm_vcpu *vcpu,
+ struct sys_reg_params *params)
+{
+ u8 hsr_ec = kvm_vcpu_trap_get_class(vcpu);
+ int cp;
+
+ switch(hsr_ec) {
+ case ESR_EL2_EC_CP15_32:
+ case ESR_EL2_EC_CP15_64:
+ cp = 15;
+ break;
+ case ESR_EL2_EC_CP14_MR:
+ case ESR_EL2_EC_CP14_64:
+ cp = 14;
+ break;
+ default:
+ WARN_ON((cp = -1));
+ }
+
+ kvm_err("Unsupported guest CP%d access at: %08lx\n",
+ cp, *vcpu_pc(vcpu));
print_sys_reg_instr(params);
kvm_inject_undefined(vcpu);
}

/**
- * kvm_handle_cp15_64 -- handles a mrrc/mcrr trap on a guest CP15 access
+ * kvm_handle_cp_64 -- handles a mrrc/mcrr trap on a guest CP15 access
* @vcpu: The VCPU pointer
* @run: The kvm_run struct
*/
-int kvm_handle_cp15_64(struct kvm_vcpu *vcpu, struct kvm_run *run)
+static int kvm_handle_cp_64(struct kvm_vcpu *vcpu,
+ const struct sys_reg_desc *global,
+ size_t nr_global,
+ const struct sys_reg_desc *target_specific,
+ size_t nr_specific)
{
struct sys_reg_params params;
u32 hsr = kvm_vcpu_get_hsr(vcpu);
@@ -665,8 +701,14 @@ int kvm_handle_cp15_64(struct kvm_vcpu *vcpu, struct kvm_run *run)
*vcpu_reg(vcpu, params.Rt) = val;
}

- emulate_cp15(vcpu, &params);
+ if (!emulate_cp(vcpu, &params, target_specific, nr_specific))
+ goto out;
+ if (!emulate_cp(vcpu, &params, global, nr_global))
+ goto out;

+ unhandled_cp_access(vcpu, &params);
+
+out:
/* Do the opposite hack for the read side */
if (!params.is_write) {
u64 val = *vcpu_reg(vcpu, params.Rt);
@@ -682,7 +724,11 @@ int kvm_handle_cp15_64(struct kvm_vcpu *vcpu, struct kvm_run *run)
* @vcpu: The VCPU pointer
* @run: The kvm_run struct
*/
-int kvm_handle_cp15_32(struct kvm_vcpu *vcpu, struct kvm_run *run)
+static int kvm_handle_cp_32(struct kvm_vcpu *vcpu,
+ const struct sys_reg_desc *global,
+ size_t nr_global,
+ const struct sys_reg_desc *target_specific,
+ size_t nr_specific)
{
struct sys_reg_params params;
u32 hsr = kvm_vcpu_get_hsr(vcpu);
@@ -697,10 +743,51 @@ int kvm_handle_cp15_32(struct kvm_vcpu *vcpu, struct kvm_run *run)
params.Op1 = (hsr >> 14) & 0x7;
params.Op2 = (hsr >> 17) & 0x7;

- emulate_cp15(vcpu, &params);
+ if (!emulate_cp(vcpu, &params, target_specific, nr_specific))
+ return 1;
+ if (!emulate_cp(vcpu, &params, global, nr_global))
+ return 1;
+
+ unhandled_cp_access(vcpu, &params);
return 1;
}

+int kvm_handle_cp15_64(struct kvm_vcpu *vcpu, struct kvm_run *run)
+{
+ const struct sys_reg_desc *target_specific;
+ size_t num;
+
+ target_specific = get_target_table(vcpu->arch.target, false, &num);
+ return kvm_handle_cp_64(vcpu,
+ cp15_regs, ARRAY_SIZE(cp15_regs),
+ target_specific, num);
+}
+
+int kvm_handle_cp15_32(struct kvm_vcpu *vcpu, struct kvm_run *run)
+{
+ const struct sys_reg_desc *target_specific;
+ size_t num;
+
+ target_specific = get_target_table(vcpu->arch.target, false, &num);
+ return kvm_handle_cp_32(vcpu,
+ cp15_regs, ARRAY_SIZE(cp15_regs),
+ target_specific, num);
+}
+
+int kvm_handle_cp14_64(struct kvm_vcpu *vcpu, struct kvm_run *run)
+{
+ return kvm_handle_cp_64(vcpu,
+ cp14_regs, ARRAY_SIZE(cp14_regs),
+ NULL, 0);
+}
+
+int kvm_handle_cp14_32(struct kvm_vcpu *vcpu, struct kvm_run *run)
+{
+ return kvm_handle_cp_32(vcpu,
+ cp14_regs, ARRAY_SIZE(cp14_regs),
+ NULL, 0);
+}
+
static int emulate_sys_reg(struct kvm_vcpu *vcpu,
const struct sys_reg_params *params)
{
--
1.8.3.4