[PATCH v6 12/12] ARM: KVM: Handle CP15 CR9 accesses for L2CTLR emulation

[Christoffer Dall]

From: Marc Zyngier <marc.zyng...@arm.com>

Note: This is an awful hack and will go away as soon as the emulation and
decoding code has been changed to a table-driven approach.

Signed-off-by: Marc Zyngier <marc.zyng...@arm.com>
---
 arch/arm/kvm/emulate.c |   36 ++++++++++++++++++++++++++++++++++++
 1 files changed, 36 insertions(+), 0 deletions(-)

diff --git a/arch/arm/kvm/emulate.c b/arch/arm/kvm/emulate.c
index 20269f8..4f5f2de 100644
--- a/arch/arm/kvm/emulate.c
+++ b/arch/arm/kvm/emulate.c
@@ -206,6 +206,39 @@ int kvm_handle_cp14_access(struct kvm_vcpu *vcpu, struct 
kvm_run *run)
 }
 
 /**
+ * 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 int emulate_cp15_c9_access(struct kvm_vcpu *vcpu,
+                                 struct coproc_params *p)
+{
+       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 (p->is_write)
+                       return 0;
+
+               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;
+
+               return 0;
+       }
+
+       /* hack alert!!! */
+       if (!p->is_write)
+               *vcpu_reg(vcpu, p->Rt1) = 0;
+       return 0;
+}
+
+/**
  * emulate_cp15_c10_access -- emulates cp15 accesses for CRn == 10
  * @vcpu: The VCPU pointer
  * @p:    The coprocessor parameters struct pointer holding trap inst. details
@@ -310,6 +343,9 @@ int kvm_handle_cp15_access(struct kvm_vcpu *vcpu, struct 
kvm_run *run)
                goto unsupp_err_out;
 
        switch (params.CRn) {
+       case 9:
+               ret = emulate_cp15_c9_access(vcpu, &params);
+               break;
        case 10:
                ret = emulate_cp15_c10_access(vcpu, &params);
                break;

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