[PATCH 25/29] arm64: KVM: 32bit handling of coprocessor traps

Marc Zyngier
2013-03-05T03:55:50Z

Provide the necessary infrastructure to trap coprocessor accesses that
occur when running 32bit guests.

Also wire SMC and HVC trapped in 32bit mode while were at it.

Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
---
arch/arm64/include/asm/kvm_coproc.h | 5 ++
arch/arm64/kvm/handle_exit.c | 7 ++
arch/arm64/kvm/sys_regs.c | 165 ++++++++++++++++++++++++++++++++++--
3 files changed, 170 insertions(+), 7 deletions(-)

diff --git a/arch/arm64/include/asm/kvm_coproc.h b/arch/arm64/include/asm/kvm_coproc.h
index e791894..0378be9 100644
--- a/arch/arm64/include/asm/kvm_coproc.h
+++ b/arch/arm64/include/asm/kvm_coproc.h
@@ -33,10 +33,15 @@ struct kvm_sys_reg_table {
struct kvm_sys_reg_target_table {
unsigned target;
struct kvm_sys_reg_table table64;
+ struct kvm_sys_reg_table table32;
};

void kvm_register_target_sys_reg_table(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_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);

#define kvm_coproc_table_init kvm_sys_reg_table_init
diff --git a/arch/arm64/kvm/handle_exit.c b/arch/arm64/kvm/handle_exit.c
index fa38230..3e61dcb 100644
--- a/arch/arm64/kvm/handle_exit.c
+++ b/arch/arm64/kvm/handle_exit.c
@@ -62,6 +62,13 @@ static int kvm_handle_wfi(struct kvm_vcpu *vcpu, struct kvm_run *run)

static exit_handle_fn arm_exit_handlers[] = {
[ESR_EL2_EC_WFI] = kvm_handle_wfi,
+ [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_LS] = kvm_handle_cp14_load_store,
+ [ESR_EL2_EC_CP14_64] = kvm_handle_cp14_access,
+ [ESR_EL2_EC_HVC32] = handle_hvc,
+ [ESR_EL2_EC_SMC32] = handle_smc,
[ESR_EL2_EC_HVC64] = handle_hvc,
[ESR_EL2_EC_SMC64] = handle_smc,
[ESR_EL2_EC_SYS64] = kvm_handle_sys_reg,
diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
index 9fc8c17..1b1cb21 100644
--- a/arch/arm64/kvm/sys_regs.c
+++ b/arch/arm64/kvm/sys_regs.c
@@ -38,6 +38,10 @@
* types are different. My gut feeling is that it should be pretty
* easy to merge, but that would be an ABI breakage -- again. VFP
* would also need to be abstracted.
+ *
+ * For AArch32, we only take care of what is being trapped. Anything
+ * that has to do with init and userspace access has to go via the
+ * 64bit interface.
*/

/* 3 bits per cache level, as per CLIDR, but non-existent caches always 0 */
@@ -256,6 +260,36 @@ static const struct sys_reg_desc sys_reg_descs[] = {
/* TPIDRRO_EL0 */
{ Op0(0b11), Op1(0b011), CRn(0b1101), CRm(0b0000), Op2(0b011),
NULL, reset_unknown, TPIDRRO_EL0 },
+
+ /* DACR32_EL2 */
+ { Op0(0b11), Op1(0b100), CRn(0b0011), CRm(0b0000), Op2(0b000),
+ NULL, reset_unknown, DACR32_EL2 },
+ /* IFSR32_EL2 */
+ { Op0(0b11), Op1(0b100), CRn(0b0101), CRm(0b0000), Op2(0b001),
+ NULL, reset_unknown, IFSR32_EL2 },
+};
+
+/* Trapped cp15 registers */
+static const struct sys_reg_desc cp15_regs[] = {
+ /*
+ * DC{C,I,CI}SW operations:
+ */
+ { Op1( 0), CRn( 7), CRm( 6), Op2( 2), access_dcsw },
+ { Op1( 0), CRn( 7), CRm(10), Op2( 2), access_dcsw },
+ { Op1( 0), CRn( 7), CRm(14), Op2( 2), access_dcsw },
+ { Op1( 0), CRn( 9), CRm(12), Op2( 0), pm_fake },
+ { Op1( 0), CRn( 9), CRm(12), Op2( 1), pm_fake },
+ { Op1( 0), CRn( 9), CRm(12), Op2( 2), pm_fake },
+ { Op1( 0), CRn( 9), CRm(12), Op2( 3), pm_fake },
+ { Op1( 0), CRn( 9), CRm(12), Op2( 5), pm_fake },
+ { Op1( 0), CRn( 9), CRm(12), Op2( 6), pm_fake },
+ { Op1( 0), CRn( 9), CRm(12), Op2( 7), pm_fake },
+ { Op1( 0), CRn( 9), CRm(13), Op2( 0), pm_fake },
+ { Op1( 0), CRn( 9), CRm(13), Op2( 1), pm_fake },
+ { Op1( 0), CRn( 9), CRm(13), Op2( 2), pm_fake },
+ { Op1( 0), CRn( 9), CRm(14), Op2( 0), pm_fake },
+ { Op1( 0), CRn( 9), CRm(14), Op2( 1), pm_fake },
+ { Op1( 0), CRn( 9), CRm(14), Op2( 2), pm_fake },
};

/* Target specific emulation tables */
@@ -267,13 +301,20 @@ void kvm_register_target_sys_reg_table(struct kvm_sys_reg_target_table *table)
}

/* Get specific register table for this target. */
-static const struct sys_reg_desc *get_target_table(unsigned target, size_t *num)
+static const struct sys_reg_desc *get_target_table(unsigned target,
+ bool mode_is_64,
+ size_t *num)
{
struct kvm_sys_reg_target_table *table;

table = target_tables[target];
- *num = table->table64.num;
- return table->table64.table;
+ if (mode_is_64) {
+ *num = table->table64.num;
+ return table->table64.table;
+ } else {
+ *num = table->table32.num;
+ return table->table32.table;
+ }
}

static const struct sys_reg_desc *find_reg(const struct sys_reg_params *params,
@@ -301,13 +342,123 @@ static const struct sys_reg_desc *find_reg(const struct sys_reg_params *params,
return NULL;
}

+int kvm_handle_cp14_load_store(struct kvm_vcpu *vcpu, struct kvm_run *run)
+{
+ kvm_inject_undefined(vcpu);
+ return 1;
+}
+
+int kvm_handle_cp14_access(struct kvm_vcpu *vcpu, struct kvm_run *run)
+{
+ kvm_inject_undefined(vcpu);
+ return 1;
+}
+
+static int emulate_cp15(struct kvm_vcpu *vcpu,
+ const struct sys_reg_params *params)
+{
+ size_t num;
+ const struct sys_reg_desc *table, *r;
+
+ table = get_target_table(vcpu->arch.target, false, &num);
+
+ /* 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 we don't have an accessor, we should never get here! */
+ BUG_ON(!r->access);
+
+ if (likely(r->access(vcpu, params, r))) {
+ /* Skip instruction, since it was emulated */
+ kvm_skip_instr(vcpu, kvm_vcpu_trap_il_is32bit(vcpu));
+ return 1;
+ }
+ /* If access function fails, it should complain. */
+ } else {
+ kvm_err("Unsupported guest CP15 access at: %08lx\n",
+ *vcpu_pc(vcpu));
+ print_sys_reg_instr(params);
+ }
+ kvm_inject_undefined(vcpu);
+ return 1;
+}
+
+/**
+ * kvm_handle_cp15_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)
+{
+ struct sys_reg_params params;
+ u32 hsr = kvm_vcpu_get_hsr(vcpu);
+ int Rt2 = (hsr >> 10) & 0xf;
+ int ret;
+
+ params.CRm = (hsr >> 1) & 0xf;
+ params.Rt = (hsr >> 5) & 0xf;
+ params.is_write = ((hsr & 1) == 0);
+
+ params.Op0 = 0;
+ params.Op1 = (hsr >> 16) & 0xf;
+ params.Op2 = 0;
+ params.CRn = 0;
+
+ /*
+ * Massive hack here. Store Rt2 in the top 32bits so we only
+ * have one register to deal with. As we use the same trap
+ * backends between AArch32 and AArch64, we get away with it.
+ */
+ if (params.is_write) {
+ u64 val = *vcpu_reg(vcpu, params.Rt);
+ val &= 0xffffffff;
+ val |= *vcpu_reg(vcpu, Rt2) << 32;
+ *vcpu_reg(vcpu, params.Rt) = val;
+ }
+
+ ret = emulate_cp15(vcpu, &params);
+
+ /* Reverse hack here */
+ if (ret && !params.is_write) {
+ u64 val = *vcpu_reg(vcpu, params.Rt);
+ val >>= 32;
+ *vcpu_reg(vcpu, Rt2) = val;
+ }
+
+ return ret;
+}
+
+/**
+ * kvm_handle_cp15_32 -- handles a mrc/mcr trap on a guest CP15 access
+ * @vcpu: The VCPU pointer
+ * @run: The kvm_run struct
+ */
+int kvm_handle_cp15_32(struct kvm_vcpu *vcpu, struct kvm_run *run)
+{
+ struct sys_reg_params params;
+ u32 hsr = kvm_vcpu_get_hsr(vcpu);
+
+ params.CRm = (hsr >> 1) & 0xf;
+ params.Rt = (hsr >> 5) & 0xf;
+ params.is_write = ((hsr & 1) == 0);
+ params.CRn = (hsr >> 10) & 0xf;
+ params.Op0 = 0;
+ params.Op1 = (hsr >> 14) & 0x7;
+ params.Op2 = (hsr >> 17) & 0x7;
+
+ return emulate_cp15(vcpu, &params);
+}
+
static int emulate_sys_reg(struct kvm_vcpu *vcpu,
const struct sys_reg_params *params)
{
size_t num;
const struct sys_reg_desc *table, *r;

- table = get_target_table(vcpu->arch.target, &num);
+ table = get_target_table(vcpu->arch.target, true, &num);

/* Search target-specific then generic table. */
r = find_reg(params, table, num);
@@ -412,7 +563,7 @@ static const struct sys_reg_desc *index_to_sys_reg_desc(struct kvm_vcpu *vcpu,
if (!index_to_params(id, &params))
return NULL;

- table = get_target_table(vcpu->arch.target, &num);
+ table = get_target_table(vcpu->arch.target, true, &num);
r = find_reg(&params, table, num);
if (!r)
r = find_reg(&params, sys_reg_descs, ARRAY_SIZE(sys_reg_descs));
@@ -835,7 +986,7 @@ static int walk_sys_regs(struct kvm_vcpu *vcpu, u64 __user *uind)
size_t num;

/* We check for duplicates here, to allow arch-specific overrides. */
- i1 = get_target_table(vcpu->arch.target, &num);
+ i1 = get_target_table(vcpu->arch.target, true, &num);
end1 = i1 + num;
i2 = sys_reg_descs;
end2 = sys_reg_descs + ARRAY_SIZE(sys_reg_descs);
@@ -953,7 +1104,7 @@ void kvm_reset_sys_regs(struct kvm_vcpu *vcpu)
/* Generic chip reset first (so target could override). */
reset_sys_reg_descs(vcpu, sys_reg_descs, ARRAY_SIZE(sys_reg_descs));

- table = get_target_table(vcpu->arch.target, &num);
+ table = get_target_table(vcpu->arch.target, true, &num);
reset_sys_reg_descs(vcpu, table, num);

for (num = 1; num < NR_SYS_REGS; num++)
--
1.7.12.4