[PATCH v6 04/12] KVM: arm: guest debug, add stub KVM_SET_GUEST_DEBUG ioctl

From: Alex BennÃe
Date: Fri Jun 19 2015 - 08:25:35 EST


This commit adds a stub function to support the KVM_SET_GUEST_DEBUG
ioctl. Any unsupported flag will return -EINVAL. For now, only
KVM_GUESTDBG_ENABLE is supported, although it won't have any effects.

Signed-off-by: Alex BennÃe <alex.bennee@xxxxxxxxxx>.
Reviewed-by: Christoffer Dall <christoffer.dall@xxxxxxxxxx>

---
v2
- simplified form of the ioctl (stuff will go into setup_debug)
v3
- KVM_GUESTDBG_VALID->KVM_GUESTDBG_VALID_MASK
- move mask check to the top of function
- add ioctl doc header
- split capability into separate patch
- tweaked commit wording w.r.t return of -EINVAL
v4
- add r-b-tag
---
Documentation/virtual/kvm/api.txt | 2 +-
arch/arm/kvm/arm.c | 23 ++++++++++++++++++++++-
2 files changed, 23 insertions(+), 2 deletions(-)

diff --git a/Documentation/virtual/kvm/api.txt b/Documentation/virtual/kvm/api.txt
index c34c32d..ba635c7 100644
--- a/Documentation/virtual/kvm/api.txt
+++ b/Documentation/virtual/kvm/api.txt
@@ -2645,7 +2645,7 @@ handled.
4.87 KVM_SET_GUEST_DEBUG

Capability: KVM_CAP_SET_GUEST_DEBUG
-Architectures: x86, s390, ppc
+Architectures: x86, s390, ppc, arm64
Type: vcpu ioctl
Parameters: struct kvm_guest_debug (in)
Returns: 0 on success; -1 on error
diff --git a/arch/arm/kvm/arm.c b/arch/arm/kvm/arm.c
index d9631ec..52a1d4d38 100644
--- a/arch/arm/kvm/arm.c
+++ b/arch/arm/kvm/arm.c
@@ -302,10 +302,31 @@ void kvm_arch_vcpu_put(struct kvm_vcpu *vcpu)
kvm_arm_set_running_vcpu(NULL);
}

+#define KVM_GUESTDBG_VALID_MASK (KVM_GUESTDBG_ENABLE)
+
+/**
+ * kvm_arch_vcpu_ioctl_set_guest_debug - set up guest debugging
+ * @kvm: pointer to the KVM struct
+ * @kvm_guest_debug: the ioctl data buffer
+ *
+ * This sets up and enables the VM for guest debugging. Userspace
+ * passes in a control flag to enable different debug types and
+ * potentially other architecture specific information in the rest of
+ * the structure.
+ */
int kvm_arch_vcpu_ioctl_set_guest_debug(struct kvm_vcpu *vcpu,
struct kvm_guest_debug *dbg)
{
- return -EINVAL;
+ if (dbg->control & ~KVM_GUESTDBG_VALID_MASK)
+ return -EINVAL;
+
+ if (dbg->control & KVM_GUESTDBG_ENABLE) {
+ vcpu->guest_debug = dbg->control;
+ } else {
+ /* If not enabled clear all flags */
+ vcpu->guest_debug = 0;
+ }
+ return 0;
}


--
2.4.3

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