From: John Johnson <john.g.johnson@oracle.com>
To: Stefan Hajnoczi <stefanha@redhat.com>
Cc: Elena Ufimtseva <elena.ufimtseva@oracle.com>,
Jag Raman <jag.raman@oracle.com>,
Swapnil Ingle <swapnil.ingle@nutanix.com>,
John Levon <john.levon@nutanix.com>,
QEMU Devel Mailing List <qemu-devel@nongnu.org>,
Alex Williamson <alex.williamson@redhat.com>,
"thanos.makatos@nutanix.com" <thanos.makatos@nutanix.com>
Subject: Re: [PATCH RFC v2 08/16] vfio-user: get region info
Date: Thu, 9 Sep 2021 05:35:40 +0000 [thread overview]
Message-ID: <59C70EB8-E4D5-4F54-B0E8-A5A10334C0EC@oracle.com> (raw)
In-Reply-To: <YTd3zRAjg51tzzfd@stefanha-x1.localdomain>
> On Sep 7, 2021, at 7:31 AM, Stefan Hajnoczi <stefanha@redhat.com> wrote:
>
> On Mon, Aug 16, 2021 at 09:42:41AM -0700, Elena Ufimtseva wrote:
>> @@ -1514,6 +1515,16 @@ bool vfio_get_info_dma_avail(struct vfio_iommu_type1_info *info,
>> return true;
>> }
>>
>> +static int vfio_get_region_info_remfd(VFIODevice *vbasedev, int index)
>> +{
>> + struct vfio_region_info *info;
>> +
>> + if (vbasedev->regions == NULL || vbasedev->regions[index] == NULL) {
>> + vfio_get_region_info(vbasedev, index, &info);
>> + }
>
> Maybe this will be called from other places in the future, but the
> vfio_region_setup() caller below already invoked vfio_get_region_info()
> so I'm not sure it's necessary to do this again?
>
> Perhaps add an int *remfd argument to vfio_get_region_info(). That way
> vfio_get_region_info_remfd() isn't necessary.
>
I think they could be combined, but the region capabilities are
retrieved with separate calls to vfio_get_region_info_cap(), so I followed
that precedent.
>> @@ -2410,6 +2442,24 @@ int vfio_get_region_info(VFIODevice *vbasedev, int index,
>> struct vfio_region_info **info)
>> {
>> size_t argsz = sizeof(struct vfio_region_info);
>> + int fd = -1;
>> + int ret;
>> +
>> + /* create region cache */
>> + if (vbasedev->regions == NULL) {
>> + vbasedev->regions = g_new0(struct vfio_region_info *,
>> + vbasedev->num_regions);
>> + if (vbasedev->proxy != NULL) {
>> + vbasedev->regfds = g_new0(int, vbasedev->num_regions);
>> + }
>> + }
>> + /* check cache */
>> + if (vbasedev->regions[index] != NULL) {
>> + *info = g_malloc0(vbasedev->regions[index]->argsz);
>> + memcpy(*info, vbasedev->regions[index],
>> + vbasedev->regions[index]->argsz);
>> + return 0;
>> + }
>
> Why is it necessary to introduce a cache? Is it to avoid passing the
> same fd multiple times?
>
Yes. For polled regions, the server returns an FD with each
message, so there would be an FD leak if I didn’t check that the region
hadn’t already returned one. Since I had to cache the FD anyway, I
cached the whole struct.
>>
>> *info = g_malloc0(argsz);
>>
>> @@ -2417,7 +2467,17 @@ int vfio_get_region_info(VFIODevice *vbasedev, int index,
>> retry:
>> (*info)->argsz = argsz;
>>
>> - if (ioctl(vbasedev->fd, VFIO_DEVICE_GET_REGION_INFO, *info)) {
>> + if (vbasedev->proxy != NULL) {
>> + VFIOUserFDs fds = { 0, 1, &fd};
>> +
>> + ret = vfio_user_get_region_info(vbasedev, index, *info, &fds);
>> + } else {
>> + ret = ioctl(vbasedev->fd, VFIO_DEVICE_GET_REGION_INFO, *info);
>> + if (ret < 0) {
>> + ret = -errno;
>> + }
>> + }
>> + if (ret != 0) {
>> g_free(*info);
>> *info = NULL;
>> return -errno;
>> @@ -2426,10 +2486,22 @@ retry:
>> if ((*info)->argsz > argsz) {
>> argsz = (*info)->argsz;
>> *info = g_realloc(*info, argsz);
>> + if (fd != -1) {
>> + close(fd);
>> + fd = -1;
>> + }
>>
>> goto retry;
>> }
>>
>> + /* fill cache */
>> + vbasedev->regions[index] = g_malloc0(argsz);
>> + memcpy(vbasedev->regions[index], *info, argsz);
>> + *vbasedev->regions[index] = **info;
>
> The previous line already copied the contents of *info. What is the
> purpose of this assignment?
>
That might be a mis-merge. The struct assignment was a bug
fixed several revs ago with the memcpy() call.
>> + if (vbasedev->regfds != NULL) {
>> + vbasedev->regfds[index] = fd;
>> + }
>> +
>> return 0;
>> }
>>
>> diff --git a/hw/vfio/user.c b/hw/vfio/user.c
>> index b584b8e0f2..91b51f37df 100644
>> --- a/hw/vfio/user.c
>> +++ b/hw/vfio/user.c
>> @@ -734,3 +734,36 @@ int vfio_user_get_info(VFIODevice *vbasedev)
>> vbasedev->reset_works = !!(msg.flags & VFIO_DEVICE_FLAGS_RESET);
>> return 0;
>> }
>> +
>> +int vfio_user_get_region_info(VFIODevice *vbasedev, int index,
>> + struct vfio_region_info *info, VFIOUserFDs *fds)
>> +{
>> + g_autofree VFIOUserRegionInfo *msgp = NULL;
>> + int size;
>
> Please use uint32_t size instead of int size to prevent possible
> signedness issues:
> - VFIOUserRegionInfo->argsz is uint32_t.
> - sizeof(VFIOUserHdr) is size_t.
> - The vfio_user_request_msg() size argument is uint32_t.
OK
JJ
next prev parent reply other threads:[~2021-09-09 5:37 UTC|newest]
Thread overview: 108+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-08-16 16:42 [PATCH RFC v2 00/16] vfio-user implementation Elena Ufimtseva
2021-08-16 16:42 ` [PATCH RFC v2 01/16] vfio-user: introduce vfio-user protocol specification Elena Ufimtseva
2021-08-17 23:04 ` Alex Williamson
2021-08-19 9:28 ` Swapnil Ingle
2021-08-19 15:32 ` John Johnson
2021-08-19 16:26 ` Alex Williamson
2021-08-16 16:42 ` [PATCH RFC v2 02/16] vfio-user: add VFIO base abstract class Elena Ufimtseva
2021-08-16 16:42 ` [PATCH RFC v2 03/16] vfio-user: Define type vfio_user_pci_dev_info Elena Ufimtseva
2021-08-24 13:52 ` Stefan Hajnoczi
2021-08-16 16:42 ` [PATCH RFC v2 04/16] vfio-user: connect vfio proxy to remote server Elena Ufimtseva
2021-08-18 18:47 ` Alex Williamson
2021-08-19 14:10 ` John Johnson
2021-08-24 14:15 ` Stefan Hajnoczi
2021-08-30 3:00 ` John Johnson
2021-09-07 13:21 ` Stefan Hajnoczi
2021-09-09 5:11 ` John Johnson
2021-09-09 6:29 ` Stefan Hajnoczi
2021-09-10 5:25 ` John Johnson
2021-09-13 12:35 ` Stefan Hajnoczi
2021-09-13 17:23 ` John Johnson
2021-09-14 13:06 ` Stefan Hajnoczi
2021-09-15 0:21 ` John Johnson
2021-09-15 13:04 ` Stefan Hajnoczi
2021-09-15 19:14 ` John Johnson
2021-09-16 11:49 ` Stefan Hajnoczi
2021-08-16 16:42 ` [PATCH RFC v2 05/16] vfio-user: define VFIO Proxy and communication functions Elena Ufimtseva
2021-08-24 15:14 ` Stefan Hajnoczi
2021-08-30 3:04 ` John Johnson
2021-09-07 13:35 ` Stefan Hajnoczi
2021-08-16 16:42 ` [PATCH RFC v2 06/16] vfio-user: negotiate version with remote server Elena Ufimtseva
2021-08-24 15:59 ` Stefan Hajnoczi
2021-08-30 3:08 ` John Johnson
2021-09-07 13:52 ` Stefan Hajnoczi
2021-08-16 16:42 ` [PATCH RFC v2 07/16] vfio-user: get device info Elena Ufimtseva
2021-08-24 16:04 ` Stefan Hajnoczi
2021-08-30 3:11 ` John Johnson
2021-09-07 13:54 ` Stefan Hajnoczi
2021-08-16 16:42 ` [PATCH RFC v2 08/16] vfio-user: get region info Elena Ufimtseva
2021-09-07 14:31 ` Stefan Hajnoczi
2021-09-09 5:35 ` John Johnson [this message]
2021-09-09 5:59 ` Stefan Hajnoczi
2021-08-16 16:42 ` [PATCH RFC v2 09/16] vfio-user: region read/write Elena Ufimtseva
2021-09-07 14:41 ` Stefan Hajnoczi
2021-09-07 17:24 ` John Levon
2021-09-09 6:00 ` John Johnson
2021-09-09 12:05 ` John Levon
2021-09-10 6:07 ` John Johnson
2021-09-10 12:16 ` John Levon
2021-08-16 16:42 ` [PATCH RFC v2 10/16] vfio-user: pci_user_realize PCI setup Elena Ufimtseva
2021-09-07 15:00 ` Stefan Hajnoczi
2021-08-16 16:42 ` [PATCH RFC v2 11/16] vfio-user: get and set IRQs Elena Ufimtseva
2021-09-07 15:14 ` Stefan Hajnoczi
2021-09-09 5:50 ` John Johnson
2021-09-09 13:50 ` Stefan Hajnoczi
2021-08-16 16:42 ` [PATCH RFC v2 12/16] vfio-user: proxy container connect/disconnect Elena Ufimtseva
2021-09-08 8:30 ` Stefan Hajnoczi
2021-08-16 16:42 ` [PATCH RFC v2 13/16] vfio-user: dma map/unmap operations Elena Ufimtseva
2021-09-08 9:16 ` Stefan Hajnoczi
2021-08-16 16:42 ` [PATCH RFC v2 14/16] vfio-user: dma read/write operations Elena Ufimtseva
2021-09-08 9:51 ` Stefan Hajnoczi
2021-09-08 11:03 ` John Levon
2021-08-16 16:42 ` [PATCH RFC v2 15/16] vfio-user: pci reset Elena Ufimtseva
2021-09-08 9:56 ` Stefan Hajnoczi
2021-08-16 16:42 ` [PATCH RFC v2 16/16] vfio-user: migration support Elena Ufimtseva
2021-09-08 10:04 ` Stefan Hajnoczi
2021-08-27 17:53 ` [PATCH RFC server v2 00/11] vfio-user server in QEMU Jagannathan Raman
2021-08-27 17:53 ` [PATCH RFC server v2 01/11] vfio-user: build library Jagannathan Raman
2021-08-27 18:05 ` Jag Raman
2021-09-08 12:25 ` Stefan Hajnoczi
2021-09-10 15:21 ` Philippe Mathieu-Daudé
2021-09-13 12:15 ` Stefan Hajnoczi
2021-09-10 15:20 ` Philippe Mathieu-Daudé
2021-09-10 17:08 ` Jag Raman
2021-09-11 22:29 ` John Levon
2021-09-13 10:19 ` Philippe Mathieu-Daudé
2021-08-27 17:53 ` [PATCH RFC server v2 02/11] vfio-user: define vfio-user object Jagannathan Raman
2021-09-08 12:37 ` Stefan Hajnoczi
2021-09-10 14:04 ` Jag Raman
2021-08-27 17:53 ` [PATCH RFC server v2 03/11] vfio-user: instantiate vfio-user context Jagannathan Raman
2021-09-08 12:40 ` Stefan Hajnoczi
2021-09-10 14:58 ` Jag Raman
2021-08-27 17:53 ` [PATCH RFC server v2 04/11] vfio-user: find and init PCI device Jagannathan Raman
2021-09-08 12:43 ` Stefan Hajnoczi
2021-09-10 15:02 ` Jag Raman
2021-08-27 17:53 ` [PATCH RFC server v2 05/11] vfio-user: run vfio-user context Jagannathan Raman
2021-09-08 12:58 ` Stefan Hajnoczi
2021-09-08 13:37 ` John Levon
2021-09-08 15:02 ` Stefan Hajnoczi
2021-09-08 15:21 ` John Levon
2021-09-08 15:46 ` Stefan Hajnoczi
2021-08-27 17:53 ` [PATCH RFC server v2 06/11] vfio-user: handle PCI config space accesses Jagannathan Raman
2021-09-09 7:27 ` Stefan Hajnoczi
2021-09-10 16:22 ` Jag Raman
2021-09-13 12:13 ` Stefan Hajnoczi
2021-08-27 17:53 ` [PATCH RFC server v2 07/11] vfio-user: handle DMA mappings Jagannathan Raman
2021-09-09 7:29 ` Stefan Hajnoczi
2021-08-27 17:53 ` [PATCH RFC server v2 08/11] vfio-user: handle PCI BAR accesses Jagannathan Raman
2021-09-09 7:37 ` Stefan Hajnoczi
2021-09-10 16:36 ` Jag Raman
2021-08-27 17:53 ` [PATCH RFC server v2 09/11] vfio-user: handle device interrupts Jagannathan Raman
2021-09-09 7:40 ` Stefan Hajnoczi
2021-08-27 17:53 ` [PATCH RFC server v2 10/11] vfio-user: register handlers to facilitate migration Jagannathan Raman
2021-09-09 8:14 ` Stefan Hajnoczi
2021-08-27 17:53 ` [PATCH RFC server v2 11/11] vfio-user: acceptance test Jagannathan Raman
2021-09-08 10:08 ` [PATCH RFC server v2 00/11] vfio-user server in QEMU Stefan Hajnoczi
2021-09-08 12:06 ` Jag Raman
2021-09-09 8:17 ` Stefan Hajnoczi
2021-09-10 14:02 ` Jag Raman
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