On Wed, Mar 16, 2016 at 10:30:36AM +0000, Peter Maydell wrote:
> On 8 March 2016 at 07:36, Peter Xu <pet...@redhat.com> wrote:
> > For emulated GIC capabilities, currently only gicv2 is supported. We
> > need to add gicv3 in when emulated gicv3 ready. For KVM accelerated ARM
> > VM, we detect the capability bits using ioctls.
> >
> > When probing the KVM capabilities, we cannot leverage existing helper
> > functions like kvm_create_device() since QEMU might be using TCG while
> > probing (actually this is the case for libvirt probing). So, one
> > temporary VM is created to do the probing.
> >
> > Signed-off-by: Peter Xu <pet...@redhat.com>
> > ---
> > target-arm/machine.c | 94
> > +++++++++++++++++++++++++++++++++++++++++++++++++++-
> > 1 file changed, 93 insertions(+), 1 deletion(-)
> >
> > diff --git a/target-arm/machine.c b/target-arm/machine.c
> > index 813909e..8f52f74 100644
> > --- a/target-arm/machine.c
> > +++ b/target-arm/machine.c
> > @@ -1,3 +1,5 @@
> > +#include <linux/kvm.h>
>
> This will break compilation on non-Linux hosts; you can't include
> linux headers like this.
>
> (This is all in the wrong file anyway, machine.c is for migration.)
Okay. Will move all kvm lines into kvm*.c.
>
> > +#include <sys/ioctl.h>
> > #include "qemu/osdep.h"
> > #include "hw/hw.h"
> > #include "hw/boards.h"
> > @@ -347,7 +349,97 @@ const char *gicv3_class_name(void)
> > exit(1);
> > }
> >
> > +static GICCapability *gic_cap_new(int version)
> > +{
> > + GICCapability *cap = g_new0(GICCapability, 1);
> > + cap->version = version;
> > + /* by default, support none */
> > + cap->emulated = false;
> > + cap->kernel = false;
> > + return cap;
> > +}
> > +
> > +static GICCapabilityList *gic_cap_list_add(GICCapabilityList *head,
> > + GICCapability *cap)
> > +{
> > + GICCapabilityList *item = g_new0(GICCapabilityList, 1);
> > + item->value = cap;
> > + item->next = head;
> > + return item;
> > +}
> > +
> > +#ifdef CONFIG_KVM
> > +/* Test whether KVM support specific device. */
> > +static inline int kvm_support_device(int vmfd, uint64_t type)
> > +{
> > + struct kvm_create_device create_dev = {
> > + .type = type,
> > + .fd = -1,
> > + .flags = KVM_CREATE_DEVICE_TEST,
> > + };
> > + return ioctl(vmfd, KVM_CREATE_DEVICE, &create_dev);
> > +}
> > +#endif
>
> This is not ARM specific so it should go in kvm-all.c.
Will do.
>
> > +
> > GICCapabilityList *qmp_query_gic_capabilities(Error **errp)
> > {
> > - return NULL;
> > + GICCapabilityList *head = NULL;
> > + GICCapability *v2 = gic_cap_new(2), *v3 = gic_cap_new(3);
> > +
> > + v2->emulated = true;
> > + /* FIXME: we'd change to true after we get emulated GICv3. */
> > + v3->emulated = false;
> > +
> > +#ifdef CONFIG_KVM
>
> KVM specific code should be factored out and live in one of
> the target-arm/kvm*.c files.
Ok, will fix.
>
> > + {
> > + int kvm_fd = -1;
> > + int vmfd = -1;
> > + /*
> > + * HACK: here we create one temporary VM, do the probing,
> > + * then release it properly.
> > + */
> > + kvm_fd = qemu_open("/dev/kvm", O_RDWR);
> > + if (kvm_fd == -1) {
> > + /* KVM may not enabled on host, which is fine. */
> > + goto out;
> > + }
> > +
> > + do {
> > + /* For ARM, VM type could only be zero now. */
> > + vmfd = ioctl(kvm_fd, KVM_CREATE_VM, 0);
> > + } while (vmfd == -EINTR);
> > +
> > + if (vmfd < 0) {
> > + goto kvm_fd_close;
> > + }
>
> Rather than open-coding this you might as well use
> kvm_arm_creat_scratch_host_vcpu() (you don't need the vcpu fd but
> it's pretty harmless to create it.)
Thanks for the func pointer! That's what I was looking for.
>
>
> > +
> > + if (ioctl(kvm_fd, KVM_CHECK_EXTENSION,
> > + KVM_CAP_DEVICE_CTRL) <= 0) {
> > + /* older version of KVM possibly */
> > + goto kvm_vmfd_close;
> > + }
>
> Do this in kvm_support_device() [mostly just to parallel how
> kvm_create_device() does it.]
Will fix.
Thanks!
-- peterx
