Re: [libvirt] [PATCH v7 3/4] kvm: add kvm_device_supported() helper function

This can be used when probing whether KVM support specific device. Here, a raw vmfd is used. Signed-off-by: Peter Xu <peterx(a)redhat.com&gt;

--- include/sysemu/kvm.h | 9 +++++++++ kvm-all.c | 15 +++++++++++++++ 2 files changed, 24 insertions(+) diff --git a/include/sysemu/kvm.h b/include/sysemu/kvm.h index 6695fa7..0e18f15 100644 --- a/include/sysemu/kvm.h +++ b/include/sysemu/kvm.h @@ -306,6 +306,15 @@ void kvm_device_access(int fd, int group, uint64_t attr, */ int kvm_create_device(KVMState *s, uint64_t type, bool test); +/** + * kvm_device_supported - probe whether KVM supports specific device + * + * @vmfd: The fd handler for VM + * @type: type of device + * + * @return: true if supported, otherwise false. + */ +bool kvm_device_supported(int vmfd, uint64_t type); /* Arch specific hooks */ diff --git a/kvm-all.c b/kvm-all.c index 44c0464..e7b66df 100644 --- a/kvm-all.c +++ b/kvm-all.c @@ -2339,6 +2339,21 @@ int kvm_create_device(KVMState *s, uint64_t type, bool test) return test ? 0 : create_dev.fd; } +bool kvm_device_supported(int vmfd, uint64_t type) +{ + struct kvm_create_device create_dev = { + .type = type, + .fd = -1, + .flags = KVM_CREATE_DEVICE_TEST, + }; + + if (ioctl(vmfd, KVM_CHECK_EXTENSION, KVM_CAP_DEVICE_CTRL) <= 0) { + return false; + } + + return (ioctl(vmfd, KVM_CREATE_DEVICE, &create_dev) >= 0); +} + int kvm_set_one_reg(CPUState *cs, uint64_t id, void *source) { struct kvm_one_reg reg;