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Message-ID: <1331267212.16020.rusty@rustcorp.com.au>
Date: Fri, 09 Mar 2012 14:56:52 +1030
From: Rusty Russell <rusty@...tcorp.com.au>
To: Russell King <linux@....linux.org.uk>,
linux-arm-kernel@...ts.infradead.org
CC: linux-kernel@...r.kernel.org
Subject: [PATCH 6/8] ARM: KVM: table-driven coprocessor emulation.
From: Rusty Russell <rusty@...tcorp.com.au>
To try to avoid encroaching ad-hoc emulation, drive it from
a single table, so it's clear exactly what we do and do not
emulate.
Signed-off-by: Rusty Russell <rusty@...tcorp.com.au>
---
arch/arm/kvm/emulate.c | 255 ++++++++++++++++++++++++------------------------
1 files changed, 130 insertions(+), 125 deletions(-)
diff --git a/arch/arm/kvm/emulate.c b/arch/arm/kvm/emulate.c
index d386874..bd2c3dc 100644
--- a/arch/arm/kvm/emulate.c
+++ b/arch/arm/kvm/emulate.c
@@ -165,25 +165,19 @@ struct coproc_params {
bool is_write;
};
-static void cp15_op(struct kvm_vcpu *vcpu, const struct coproc_params *p,
- enum cp15_regs cp15_reg)
-{
- if (p->is_write)
- vcpu->arch.cp15[cp15_reg] = *vcpu_reg(vcpu, p->Rt1);
- else
- *vcpu_reg(vcpu, p->Rt1) = vcpu->arch.cp15[cp15_reg];
-}
-
static void print_cp_instr(const struct coproc_params *p)
{
+ /* Look, we even formatted it for you to paste into the table! */
if (p->is_64bit) {
- kvm_debug("%s\tp15, %lu, r%lu, r%lu, c%lu",
- (p->is_write) ? "mcrr" : "mrrc",
- p->Op1, p->Rt1, p->Rt2, p->CRm);
+ kvm_debug("{ .is_64bit = true, .is_write = %s, .param ="
+ " { .CRm = %lu, .Op1 = %lu } }",
+ p->is_write ? "true" : "false", p->CRm, p->Op1);
} else {
- kvm_debug("%s\tp15, %lu, r%lu, c%lu, c%lu, %lu",
- (p->is_write) ? "mcr" : "mrc",
- p->Op1, p->Rt1, p->CRn, p->CRm, p->Op2);
+ kvm_debug("{ .is_64bit = false, .is_write = %s, .param ="
+ " { .CRn = %lu, .CRm = %lu,"
+ " .Op1 = %lu, .Op2 = %lu } }",
+ p->is_write ? "true" : "false",
+ p->CRn, p->CRm, p->Op1, p->Op2);
}
}
@@ -207,139 +201,150 @@ int kvm_handle_cp14_access(struct kvm_vcpu *vcpu, struct kvm_run *run)
return -EINVAL;
}
-/**
- * emulate_cp15_c9_access -- emulates cp15 accesses for CRn == 9
- * @vcpu: The VCPU pointer
- * @p: The coprocessor parameters struct pointer holding trap inst. details
- */
-static bool emulate_cp15_c9_access(struct kvm_vcpu *vcpu,
- const struct coproc_params *p)
+static bool ignore_write(struct kvm_vcpu *vcpu,
+ const struct coproc_params *p,
+ unsigned long arg)
{
- BUG_ON(p->CRn != 9);
- BUG_ON(p->is_64bit);
-
- if (p->CRm == 0 && p->Op1 == 1 && p->Op2 == 2) {
- /* Emulate L2CTLR access */
- u32 l2ctlr, ncores;
+ if (arg)
+ trace_kvm_emulate_cp15_imp(p->Op1, p->Rt1, p->CRn, p->CRm,
+ p->Op2, p->is_write);
+ return true;
+}
- if (p->is_write)
- return true;
+static bool read_zero(struct kvm_vcpu *vcpu,
+ const struct coproc_params *p,
+ unsigned long arg)
+{
+ if (arg)
+ trace_kvm_emulate_cp15_imp(p->Op1, p->Rt1, p->CRn, p->CRm,
+ p->Op2, p->is_write);
+ *vcpu_reg(vcpu, p->Rt1) = 0;
+ return true;
+}
- asm volatile("mrc p15, 1, %0, c9, c0, 2\n" : "=r" (l2ctlr));
- l2ctlr &= ~(3 << 24);
- ncores = atomic_read(&vcpu->kvm->online_vcpus) - 1;
- l2ctlr |= (ncores & 3) << 24;
- *vcpu_reg(vcpu, p->Rt1) = l2ctlr;
+static bool read_l2ctlr(struct kvm_vcpu *vcpu,
+ const struct coproc_params *p,
+ unsigned long arg)
+{
+ u32 l2ctlr, ncores;
- return true;
- }
+ asm volatile("mrc p15, 1, %0, c9, c0, 2\n" : "=r" (l2ctlr));
+ l2ctlr &= ~(3 << 24);
+ ncores = atomic_read(&vcpu->kvm->online_vcpus) - 1;
+ l2ctlr |= (ncores & 3) << 24;
+ *vcpu_reg(vcpu, p->Rt1) = l2ctlr;
- /* hack alert!!! */
- if (!p->is_write)
- *vcpu_reg(vcpu, p->Rt1) = 0;
return true;
}
-/**
- * emulate_cp15_c10_access -- emulates cp15 accesses for CRn == 10
- * @vcpu: The VCPU pointer
- * @p: The coprocessor parameters struct pointer holding trap inst. details
- *
- * This function may not need to exist - if we can ignore guest attempts to
- * tamper with TLB lockdowns then it should be enough to store/restore the
- * host/guest PRRR and NMRR memory remap registers and allow guest direct access
- * to these registers.
- */
-static bool emulate_cp15_c10_access(struct kvm_vcpu *vcpu,
- const struct coproc_params *p)
+static bool access_cp15_reg(struct kvm_vcpu *vcpu,
+ const struct coproc_params *p,
+ unsigned long cp15_reg)
{
- BUG_ON(p->CRn != 10);
- BUG_ON(p->is_64bit);
-
- if ((p->CRm == 0 || p->CRm == 1 || p->CRm == 4 || p->CRm == 8) &&
- (p->Op2 <= 7)) {
- /* TLB Lockdown operations - ignored */
- return true;
- }
+ if (p->is_write)
+ vcpu->arch.cp15[cp15_reg] = *vcpu_reg(vcpu, p->Rt1);
+ else
+ *vcpu_reg(vcpu, p->Rt1) = vcpu->arch.cp15[cp15_reg];
+ return true;
+}
- /*
- * The role of these registers depends on whether LPAE is defined or
- * not, but there shouldn't be any breakage in any case - we may
- * simply not respect the nomenclature here.
- */
- if (p->CRm == 2 && p->Op1 == 0 && p->Op2 == 0) {
- cp15_op(vcpu, p, c10_PRRR);
- return true;
- }
+/* Any field which is 0xFFFFFFFF == any. */
+#define ANY (-1UL)
+struct coproc_emulate {
+ unsigned long is_64;
+ unsigned long is_w;
+ struct {
+ unsigned long CRm;
+ unsigned long CRn;
+ unsigned long Op1;
+ unsigned long Op2;
+ } param;
+
+ bool (*f)(struct kvm_vcpu *,
+ const struct coproc_params *,
+ unsigned long);
+ unsigned long arg;
+};
- if (p->CRm == 2 && p->Op1 == 0 && p->Op2 == 1) {
- cp15_op(vcpu, p, c10_NMRR);
- return true;
- }
- return false;
-}
+static const struct coproc_emulate coproc_emulate[] = {
+ /* Ignore writes to L2CTLR access */
+ { .is_64 = false, .is_w = true, .f = ignore_write,
+ .param = { .CRn = 9, .CRm = 0, .Op1 = 1, .Op2 = 2 } },
+ { .is_64 = false, .is_w = false, .f = read_l2ctlr,
+ .param = { .CRn = 9, .CRm = 0, .Op1 = 1, .Op2 = 2 } },
+ /* Hack alert!!! */
+ { .is_64 = false, .is_w = true, .f = ignore_write,
+ .param = { .CRn = 9, .CRm = ANY, .Op1 = ANY, .Op2 = ANY } },
+ { .is_64 = false, .is_w = false, .f = read_zero,
+ .param = { .CRn = 9, .CRm = ANY, .Op1 = ANY, .Op2 = ANY } },
+
+ /* These CRn == 10 entries may not need to exist - if we can
+ * ignore guest attempts to tamper with TLB lockdowns then it
+ * should be enough to store/restore the host/guest PRRR and
+ * NMRR memory remap registers and allow guest direct access
+ * to these registers. */
+ /* TLB Lockdown operations - ignored */
+ { .is_64 = false, .is_w = true, .f = ignore_write,
+ .param = { .CRn = 10, .CRm = 0, .Op1 = ANY, .Op2 = ANY } },
+ { .is_64 = false, .is_w = ANY, .f = access_cp15_reg,
+ .arg = c10_PRRR,
+ .param = { .CRn = 10, .CRm = 2, .Op1 = 0, .Op2 = 0 } },
+ { .is_64 = false, .is_w = ANY, .f = access_cp15_reg,
+ .arg = c10_NMRR,
+ .param = { .CRn = 10, .CRm = 2, .Op1 = 0, .Op2 = 1 } },
+
+ /* The CP15 c15 register is architecturally implementation
+ * defined, but some guest kernels attempt to read/write a
+ * diagnostics register here. We always return 0 and ignore
+ * writes and hope for the best. */
+ { .is_64 = false, .is_w = true, .f = ignore_write, .arg = 1,
+ .param = { .CRn = 15, .CRm = ANY, .Op1 = ANY, .Op2 = ANY } },
+ { .is_64 = false, .is_w = false, .f = read_zero, .arg = 1,
+ .param = { .CRn = 15, .CRm = ANY, .Op1 = ANY, .Op2 = ANY } },
+};
-/**
- * emulate_cp15_c15_access -- emulates cp15 accesses for CRn == 15
- * @vcpu: The VCPU pointer
- * @p: The coprocessor parameters struct pointer holding trap inst. details
- *
- * The CP15 c15 register is architecturally implementation defined, but some
- * guest kernels attempt to read/write a diagnostics register here. We always
- * return 0 and ignore writes and hope for the best.
- *
- * This may need to be refined.
- */
-static bool emulate_cp15_c15_access(struct kvm_vcpu *vcpu,
- const struct coproc_params *p)
+static inline bool match(unsigned long val, unsigned long param)
{
- trace_kvm_emulate_cp15_imp(p->Op1, p->Rt1, p->CRn, p->CRm,
- p->Op2, p->is_write);
-
- if (!p->is_write)
- *vcpu_reg(vcpu, p->Rt1) = 0;
-
- return true;
+ return param == ANY || val == param;
}
static int emulate_cp15(struct kvm_vcpu *vcpu,
const struct coproc_params *params)
{
- unsigned long instr_len;
- bool ok;
-
- /* So far no mrrc/mcrr accesses are emulated */
- if (params->is_64bit)
- goto unsupp_err_out;
-
- switch (params->CRn) {
- case 9:
- ok = emulate_cp15_c9_access(vcpu, params);
- break;
- case 10:
- ok = emulate_cp15_c10_access(vcpu, params);
- break;
- case 15:
- ok = emulate_cp15_c15_access(vcpu, params);
- break;
- default:
- ok = false;
+ unsigned long instr_len, i;
+
+ for (i = 0; i < ARRAY_SIZE(coproc_emulate); i++) {
+ const struct coproc_emulate *e = &coproc_emulate[i];
+
+ if (!match(params->is_64bit, e->is_64))
+ continue;
+ if (!match(params->is_write, e->is_w))
+ continue;
+ if (!match(params->CRn, e->param.CRn))
+ continue;
+ if (!match(params->CRm, e->param.CRm))
+ continue;
+ if (!match(params->Op1, e->param.Op1))
+ continue;
+ if (!match(params->Op2, e->param.Op2))
+ continue;
+
+ /* If function fails, it should complain. */
+ if (!e->f(vcpu, params, e->arg))
+ goto fail;
+
+ /* Skip instruction, since it was emulated */
+ instr_len = ((vcpu->arch.hsr >> 25) & 1) ? 4 : 2;
+ *vcpu_reg(vcpu, 15) += instr_len;
+ return 0;
}
- if (!ok)
- goto unsupp_err_out;
-
- /* Skip instruction, since it was emulated */
- instr_len = ((vcpu->arch.hsr >> 25) & 1) ? 4 : 2;
- *vcpu_reg(vcpu, 15) += instr_len;
-
- return 0;
-
-unsupp_err_out:
- kvm_err("Unsupported guest CP15 access at: %08x\n", vcpu->arch.regs.pc);
+ kvm_err("Unsupported guest CP15 access at: %08x\n",
+ vcpu->arch.regs.pc);
print_cp_instr(params);
+fail:
return -EINVAL;
}
--
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