The ACTLR is implementation dependant, and better left untouched
by the guest.
Trap the access by ignoring writes, and let reads return the host
view of the ACTLR, adjusted to reflect whether the guest is SMP
or not.
Signed-off-by: Marc Zyngier <marc.zyngier at arm.com>
---
arch/arm/include/asm/kvm_arm.h | 2 +-
arch/arm/kvm/emulate.c | 24 ++++++++++++++++++++++++
2 files changed, 25 insertions(+), 1 deletions(-)
diff --git a/arch/arm/include/asm/kvm_arm.h b/arch/arm/include/asm/kvm_arm.h
index 29f3a36..b9e4197 100644
--- a/arch/arm/include/asm/kvm_arm.h
+++ b/arch/arm/include/asm/kvm_arm.h
@@ -49,7 +49,7 @@
#define HCR_SWIO (1 << 1)
#define HCR_VM 1
#define HCR_GUEST_MASK (HCR_TSC | HCR_TWI | HCR_VM | HCR_BSU_IS | HCR_FB | \
- HCR_AMO | HCR_IMO | HCR_FMO | HCR_SWIO)
+ HCR_TAC | HCR_AMO | HCR_IMO | HCR_FMO | HCR_SWIO)
#define HCR_VIRT_EXCP_MASK (HCR_VA | HCR_VI | HCR_VF)
/* Hyp System Control Register (HSCTLR) bits */
diff --git a/arch/arm/kvm/emulate.c b/arch/arm/kvm/emulate.c
index e356d1c..6eaa97d 100644
--- a/arch/arm/kvm/emulate.c
+++ b/arch/arm/kvm/emulate.c
@@ -238,6 +238,23 @@ static bool read_l2ctlr(struct kvm_vcpu *vcpu,
return true;
}
+static bool read_actlr(struct kvm_vcpu *vcpu,
+ const struct coproc_params *p,
+ unsigned long arg)
+{
+ u32 actlr;
+
+ asm volatile("mrc p15, 0, %0, c1, c0, 1\n" : "=r" (actlr));
+ /* Make the SMP bit consistent with the guest configuration */
+ if (atomic_read(&vcpu->kvm->online_vcpus) > 1)
+ actlr |= 1U << 6;
+ else
+ actlr &= ~(1U << 6);
+ *vcpu_reg(vcpu, p->Rt1) = actlr;
+
+ return true;
+}
+
static bool access_cp15_reg(struct kvm_vcpu *vcpu,
const struct coproc_params *p,
unsigned long cp15_reg)
@@ -278,6 +295,13 @@ struct coproc_emulate {
static const struct coproc_emulate coproc_emulate[] = {
/*
+ * ACTRL access:
+ *
+ * Ignore writes, and read returns the host settings.
+ */
+ { CRn( 1), CRm( 0), Op1( 0), Op2( 1), is32, WRITE, ignore_write},
+ { CRn( 1), CRm( 0), Op1( 0), Op2( 1), is32, READ, read_actlr},
+ /*
* L2CTLR access:
*
* Ignore writes completely.
--
1.7.7.1
