From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:38756) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1acnUX-0000sh-0F for qemu-devel@nongnu.org; Mon, 07 Mar 2016 00:14:02 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1acnUV-0006Ke-MR for qemu-devel@nongnu.org; Mon, 07 Mar 2016 00:14:00 -0500 Date: Mon, 7 Mar 2016 06:12:38 +0100 From: Andrew Jones Message-ID: <20160307051025.GB2885@localhost.redhat.com> References: <1457324608-11434-1-git-send-email-peterx@redhat.com> <1457324608-11434-4-git-send-email-peterx@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1457324608-11434-4-git-send-email-peterx@redhat.com> Subject: Re: [Qemu-devel] [PATCH v3 3/3] arm: implement query-gic-capability List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Peter Xu Cc: wei@redhat.com, peter.maydell@linaro.org, mdroth@linux.vnet.ibm.com, armbru@redhat.com, abologna@redhat.com, qemu-devel@nongnu.org, qemu-arm@nongnu.org On Mon, Mar 07, 2016 at 12:23:28PM +0800, Peter Xu 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 > --- > target-arm/machine.c | 105 ++++++++++++++++++++++++++++++++++++++++++++++++++- > 1 file changed, 104 insertions(+), 1 deletion(-) > > diff --git a/target-arm/machine.c b/target-arm/machine.c > index 60bd5c1..ff50411 100644 > --- a/target-arm/machine.c > +++ b/target-arm/machine.c > @@ -1,3 +1,5 @@ > +#include > +#include > #include "qemu/osdep.h" > #include "hw/hw.h" > #include "hw/boards.h" > @@ -347,7 +349,108 @@ 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 > +/* > + * This is merely the same as kvm_create_device(). The only > + * difference is we are using raw fds rather than KVMState, so that > + * we can use it even without kvm_state initialized. > + */ > +static int kvm_create_device_fds(int kvm_fd, int vmfd, > + uint64_t type, bool test) I don't think we need this helper function. Who else will call it? Particularly without test==true? Anyway, I think three ioctls directly called from qmp_query_gic_capability should be OK. > +{ > + int ret; > + struct kvm_create_device create_dev; > + > + create_dev.type = type; > + create_dev.fd = -1; > + create_dev.flags = test ? KVM_CREATE_DEVICE_TEST : 0; > + > + if (ioctl(kvm_fd, KVM_CHECK_EXTENSION, KVM_CAP_DEVICE_CTRL) <= 0) { > + return -ENOTSUP; > + } > + > + ret = ioctl(vmfd, KVM_CREATE_DEVICE, &create_dev); > + if (ret) { > + return ret; > + } > + > + return test ? 0 : create_dev.fd; > +} > +#endif > + > GICCapabilityList *qmp_query_gic_capability(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 > + { > + /* > + * HACK: here we create one temporary VM, do the probing, > + * then release it properly. > + */ > + int kvm_fd = -1; > + int vmfd = -1; > + > + 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; > + } > + > + /* Test KVM GICv2 */ > + if (kvm_create_device_fds(kvm_fd, vmfd, KVM_DEV_TYPE_ARM_VGIC_V2, > + true) >= 0) { > + v2->kernel = true; > + } > + > + /* Test KVM GICv3 */ > + if (kvm_create_device_fds(kvm_fd, vmfd, KVM_DEV_TYPE_ARM_VGIC_V3, > + true) >= 0) { > + v3->kernel = true; > + } > + > + close(vmfd); > +kvm_fd_close: > + close(kvm_fd); > + } > +#endif > + > +out: > + head = gic_cap_list_add(head, v2); > + head = gic_cap_list_add(head, v3); > + > + return head; > } > -- > 2.4.3 > >