On 05/09/2018 10:28 AM, Halil Pasic wrote:
On 05/08/2018 02:25 PM, Tony Krowiak wrote:Introduces a VFIO based AP device. The device is defined via the QEMU command line by specifying: -device vfio-ap,sysfsdev=<path-to-mediated-matrix-device> There may be only one vfio-ap device configured for a guest. The mediated matrix device is created by the VFIO AP device[..]+ * directory. + */ + +#include <linux/vfio.h> +#include <sys/ioctl.h> +#include "qemu/osdep.h" +#include "qapi/error.h" +#include "hw/sysbus.h" +#include "hw/vfio/vfio.h" +#include "hw/vfio/vfio-common.h" +#include "hw/s390x/ap-device.h" +#include "qemu/error-report.h" +#include "qemu/queue.h" +#include "qemu/option.h" +#include "qemu/config-file.h" +#include "cpu.h" +#include "kvm_s390x.h" +#include "sysemu/sysemu.h" + +#define VFIO_AP_DEVICE_TYPE "vfio-ap" + +typedef struct VFIOAPDevice { + APDevice apdev; + VFIODevice vdev; + QTAILQ_ENTRY(VFIOAPDevice) sibling; +} VFIOAPDevice; + +VFIOAPDevice *vfio_apdev; + +static void vfio_ap_compute_needs_reset(VFIODevice *vdev) +{ + vdev->needs_reset = false; +} + +/* + * We don't need vfio_hot_reset_multi and vfio_eoi operations for + * vfio-ap-matrix device now. + */ +struct VFIODeviceOps vfio_ap_ops = { + .vfio_compute_needs_reset = vfio_ap_compute_needs_reset, +}; +I'm not familiar with the vfio infrastructure, but AFAIR I haven't seen any substantial reset handling (QEMU or kernel). Did I miss something?
No, you didn't miss anything, there is no reset handling.
If I did not. I think this is a big problem. We need to at least zeroize the queues (e.g. on system reset) to avoid leaking sensitive information. Without this, there is no sane way to use ap-passthrough. Or am I wrong?
I do not have a definitive answer, I will have to look into it. I'm thinking that since we are using ap-passthrough, the AP bus running on the guest would be responsible for handling reset possibly by resetting or zeroizing its queues. I'll get back to you on this.
Regards, Halil
