Reset all core and cp15 registers to their architecturally defined reset
values at VCPU init time.

Signed-off-by: Christoffer Dall <c.d...@virtualopensystems.com>
---
 arch/arm/include/asm/kvm_arm.h |    6 ++
 arch/arm/kvm/exports.c         |    2 +
 arch/arm/kvm/reset.c           |  100 ++++++++++++++++++++++++++++++++++++++++
 3 files changed, 108 insertions(+)

diff --git a/arch/arm/include/asm/kvm_arm.h b/arch/arm/include/asm/kvm_arm.h
index c5bbef0..2f9d28e 100644
--- a/arch/arm/include/asm/kvm_arm.h
+++ b/arch/arm/include/asm/kvm_arm.h
@@ -19,4 +19,10 @@
 #ifndef __ARM_KVM_ARM_H__
 #define __ARM_KVM_ARM_H__
 
+/* Supported Processor Types */
+#define CORTEX_A15     (0xC0F)
+
+/* Multiprocessor Affinity Register */
+#define MPIDR_CPUID    (0x3 << 0)
+
 #endif /* __ARM_KVM_ARM_H__ */
diff --git a/arch/arm/kvm/exports.c b/arch/arm/kvm/exports.c
index 01a2e41..3e38c95 100644
--- a/arch/arm/kvm/exports.c
+++ b/arch/arm/kvm/exports.c
@@ -17,3 +17,5 @@
  */
 
 #include <linux/module.h>
+
+EXPORT_SYMBOL_GPL(smp_send_reschedule);
diff --git a/arch/arm/kvm/reset.c b/arch/arm/kvm/reset.c
index c250024..78488be 100644
--- a/arch/arm/kvm/reset.c
+++ b/arch/arm/kvm/reset.c
@@ -15,6 +15,73 @@
  * along with this program; if not, write to the Free Software
  * Foundation, 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
  */
+#include <linux/compiler.h>
+#include <linux/errno.h>
+#include <linux/sched.h>
+#include <linux/kvm_host.h>
+#include <linux/kvm.h>
+
+#include <asm/unified.h>
+#include <asm/ptrace.h>
+#include <asm/cputype.h>
+#include <asm/kvm_arm.h>
+
+#define CT_ASSERT(expr, name) extern char name[(expr) ? 1 : -1]
+#define CP15_REGS_ASSERT(_array, _name) \
+       CT_ASSERT((sizeof(_array) / sizeof(_array[0])) == nr_cp15_regs, _name)
+#define UNKNOWN 0xdecafbad
+
+/******************************************************************************
+ * Cortex-A15 Register Reset Values
+ */
+
+static const int a15_max_cpu_idx = 3;
+
+static struct kvm_vcpu_regs a15_regs_reset = {
+       .cpsr = SVC_MODE | PSR_A_BIT | PSR_I_BIT | PSR_F_BIT,
+};
+
+static u32 a15_cp15_regs_reset[][2] = {
+       { c0_MIDR,              0x412FC0F0 },
+       { c0_MPIDR,             0x00000000 }, /* see kvm_arch_vcpu_init */
+       { c1_SCTLR,             0x00C50078 },
+       { c1_ACTLR,             0x00000000 },
+       { c1_CPACR,             0x00000000 },
+       { c2_TTBR0,             UNKNOWN },
+       { c2_TTBR0_high,        UNKNOWN },
+       { c2_TTBR1,             UNKNOWN },
+       { c2_TTBR1_high,        UNKNOWN },
+       { c2_TTBCR,             0x00000000 },
+       { c3_DACR,              UNKNOWN },
+       { c5_DFSR,              UNKNOWN },
+       { c5_IFSR,              UNKNOWN },
+       { c5_ADFSR,             UNKNOWN },
+       { c5_AIFSR,             UNKNOWN },
+       { c6_DFAR,              UNKNOWN },
+       { c6_IFAR,              UNKNOWN },
+       { c10_PRRR,             0x00098AA4 },
+       { c10_NMRR,             0x44E048E0 },
+       { c12_VBAR,             0x00000000 },
+       { c13_CID,              0x00000000 },
+       { c13_TID_URW,          UNKNOWN },
+       { c13_TID_URO,          UNKNOWN },
+       { c13_TID_PRIV,         UNKNOWN },
+};
+CP15_REGS_ASSERT(a15_cp15_regs_reset, a15_cp15_regs_reset_init);
+
+static void a15_reset_vcpu(struct kvm_vcpu *vcpu)
+{
+       /*
+        * Compute guest MPIDR:
+        * (Even if we present only one VCPU to the guest on an SMP
+        * host we don't set the U bit in the MPIDR, or vice versa, as
+        * revealing the underlying hardware properties is likely to
+        * be the best choice).
+        */
+       vcpu->arch.cp15[c0_MPIDR] = (read_cpuid_mpidr() & ~MPIDR_CPUID)
+                                   | (vcpu->vcpu_id & MPIDR_CPUID);
+}
+
 
 
/*******************************************************************************
  * Exported reset function
@@ -29,5 +96,38 @@
  */
 int kvm_reset_vcpu(struct kvm_vcpu *vcpu)
 {
+       unsigned int i;
+       struct kvm_vcpu_regs *cpu_reset;
+       u32 (*cp15_reset)[2];
+       void (*cpu_reset_vcpu)(struct kvm_vcpu *vcpu);
+
+       switch (kvm_target_cpu()) {
+       case CORTEX_A15:
+               if (vcpu->vcpu_id > a15_max_cpu_idx)
+                       return -EINVAL;
+               cpu_reset = &a15_regs_reset;
+               cp15_reset = a15_cp15_regs_reset;
+               cpu_reset_vcpu = a15_reset_vcpu;
+               break;
+       default:
+               return -ENODEV;
+       }
+
+       /* Reset core registers */
+       memcpy(&vcpu->arch.regs, cpu_reset, sizeof(vcpu->arch.regs));
+
+       /* Reset CP15 registers */
+       for (i = 0; i < nr_cp15_regs; i++) {
+               if (cp15_reset[i][0] != i) {
+                       kvm_err("CP15 field %d is %d, expected %d\n",
+                               i, cp15_reset[i][0], i);
+                       return -ENXIO;
+               }
+               vcpu->arch.cp15[i] = cp15_reset[i][1];
+       }
+
+       /* Physical CPU specific runtime reset operations */
+       cpu_reset_vcpu(vcpu);
+
        return 0;
 }

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