2015-05-06 16:23:32

by Alex Bennée

Subject: [PATCH v3 04/12] KVM: arm: guest debug, add stub KVM_SET_GUEST_DEBUG ioctl

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 Bennée <[email protected]>.

---
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

diff --git a/Documentation/virtual/kvm/api.txt b/Documentation/virtual/kvm/api.txt
index cb90025..4b0132f 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;
}


--
2.3.5

2015-05-08 11:52:19

by Christoffer Dall

Subject: Re: [PATCH v3 04/12] KVM: arm: guest debug, add stub KVM_SET_GUEST_DEBUG ioctl

On Wed, May 06, 2015 at 05:23:19PM +0100, Alex Benn?e wrote:
> 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 Benn?e <[email protected]>.
>
> ---
> 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
>
> diff --git a/Documentation/virtual/kvm/api.txt b/Documentation/virtual/kvm/api.txt
> index cb90025..4b0132f 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;
> }
>

Reviewed-by: Christoffer Dall <[email protected]>