vmd(8): fix vm send/receive due to invalid hva's.

Moving some of the virtio devices to zero-copy approaches required
tracking the host-side virtual address for the gpa of virtqueues.
Upon a send/receive they are invalid as the restoring system will
most likely use a different address space layout.

Recompute the hva's on receive and NULL them on send.

ok mlarkin@

diff --git a/usr.sbin/vmd/virtio.c b/usr.sbin/vmd/virtio.c
index 0ae0fef..7371d82 100644 (file)
--- a/usr.sbin/vmd/virtio.c
+++ b/usr.sbin/vmd/virtio.c
@@ -1,4 +1,4 @@
-/*     $OpenBSD: virtio.c,v 1.99 2022/12/28 21:30:19 jmc Exp $ */
+/*     $OpenBSD: virtio.c,v 1.100 2023/04/22 19:47:35 dv Exp $ */
 
 /*
  * Copyright (c) 2015 Mike Larkin <mlarkin@openbsd.org>
@@ -2015,6 +2015,8 @@ vmmci_restore(int fd, uint32_t vm_id)
 int
 viornd_restore(int fd, struct vm_create_params *vcp)
 {
+       void *hva = NULL;
+
        log_debug("%s: receiving viornd", __func__);
        if (atomicio(read, fd, &viornd, sizeof(viornd)) != sizeof(viornd)) {
                log_warnx("%s: error reading viornd from fd", __func__);
@@ -2028,6 +2030,11 @@ viornd_restore(int fd, struct vm_create_params *vcp)
        viornd.vm_id = vcp->vcp_id;
        viornd.irq = pci_get_dev_irq(viornd.pci_id);
 
+       hva = hvaddr_mem(viornd.vq[0].q_gpa, vring_size(VIORND_QUEUE_SIZE));
+       if (hva == NULL)
+               fatal("failed to restore viornd virtqueue");
+       viornd.vq[0].q_hva = hva;
+
        return (0);
 }
 
@@ -2038,6 +2045,7 @@ vionet_restore(int fd, struct vmd_vm *vm, int *child_taps)
        struct vm_create_params *vcp = &vmc->vmc_params;
        uint8_t i;
        int ret;
+       void *hva = NULL;
 
        nr_vionet = vcp->vcp_nnics;
        if (vcp->vcp_nnics > 0) {
@@ -2079,6 +2087,18 @@ vionet_restore(int fd, struct vmd_vm *vm, int *child_taps)
                        vionet[i].vm_vmid = vm->vm_vmid;
                        vionet[i].irq = pci_get_dev_irq(vionet[i].pci_id);
 
+                       hva = hvaddr_mem(vionet[i].vq[RXQ].q_gpa,
+                           vring_size(VIONET_QUEUE_SIZE));
+                       if (hva == NULL)
+                               fatal("failed to restore vionet RX virtqueue");
+                       vionet[i].vq[RXQ].q_hva = hva;
+
+                       hva = hvaddr_mem(vionet[i].vq[TXQ].q_gpa,
+                           vring_size(VIONET_QUEUE_SIZE));
+                       if (hva == NULL)
+                               fatal("failed to restore vionet TX virtqueue");
+                       vionet[i].vq[TXQ].q_hva = hva;
+
                        memset(&vionet[i].event, 0, sizeof(struct event));
                        event_set(&vionet[i].event, vionet[i].fd,
                            EV_READ | EV_PERSIST, vionet_rx_event, &vionet[i]);
@@ -2093,6 +2113,7 @@ vioblk_restore(int fd, struct vmop_create_params *vmc,
 {
        struct vm_create_params *vcp = &vmc->vmc_params;
        uint8_t i;
+       void *hva = NULL;
 
        nr_vioblk = vcp->vcp_ndisks;
        vioblk = calloc(vcp->vcp_ndisks, sizeof(struct vioblk_dev));
@@ -2123,6 +2144,12 @@ vioblk_restore(int fd, struct vmop_create_params *vmc,
                }
                vioblk[i].vm_id = vcp->vcp_id;
                vioblk[i].irq = pci_get_dev_irq(vioblk[i].pci_id);
+
+               hva = hvaddr_mem(vioblk[i].vq[0].q_gpa,
+                   vring_size(VIOBLK_QUEUE_SIZE));
+               if (hva == NULL)
+                       fatal("failed to restore vioblk virtqueue");
+               vioblk[i].vq[0].q_hva = hva;
        }
        return (0);
 }
@@ -2130,6 +2157,9 @@ vioblk_restore(int fd, struct vmop_create_params *vmc,
 int
 vioscsi_restore(int fd, struct vm_create_params *vcp, int child_cdrom)
 {
+       void *hva = NULL;
+       unsigned int i;
+
        if (!strlen(vcp->vcp_cdrom))
                return (0);
 
@@ -2161,6 +2191,15 @@ vioscsi_restore(int fd, struct vm_create_params *vcp, int child_cdrom)
        vioscsi->vm_id = vcp->vcp_id;
        vioscsi->irq = pci_get_dev_irq(vioscsi->pci_id);
 
+       /* vioscsi uses 3 virtqueues. */
+       for (i = 0; i < 3; i++) {
+               hva = hvaddr_mem(vioscsi->vq[i].q_gpa,
+                   vring_size(VIOSCSI_QUEUE_SIZE));
+               if (hva == NULL)
+                       fatal("failed to restore vioscsi virtqueue");
+               vioscsi->vq[i].q_hva = hva;
+       }
+
        return (0);
 }
 
@@ -2194,6 +2233,9 @@ int
 viornd_dump(int fd)
 {
        log_debug("%s: sending viornd", __func__);
+
+       viornd.vq[0].q_hva = NULL;
+
        if (atomicio(vwrite, fd, &viornd, sizeof(viornd)) != sizeof(viornd)) {
                log_warnx("%s: error writing viornd to fd", __func__);
                return (-1);
@@ -2205,6 +2247,7 @@ int
 vmmci_dump(int fd)
 {
        log_debug("%s: sending vmmci", __func__);
+
        if (atomicio(vwrite, fd, &vmmci, sizeof(vmmci)) != sizeof(vmmci)) {
                log_warnx("%s: error writing vmmci to fd", __func__);
                return (-1);
@@ -2215,7 +2258,15 @@ vmmci_dump(int fd)
 int
 vionet_dump(int fd)
 {
+       int i;
+
        log_debug("%s: sending vionet", __func__);
+
+       for (i = 0; i < nr_vionet; i++) {
+               vionet[i].vq[RXQ].q_hva = NULL;
+               vionet[i].vq[TXQ].q_hva = NULL;
+       }
+
        if (atomicio(vwrite, fd, vionet,
            nr_vionet * sizeof(struct vionet_dev)) !=
            nr_vionet * sizeof(struct vionet_dev)) {
@@ -2228,7 +2279,13 @@ vionet_dump(int fd)
 int
 vioblk_dump(int fd)
 {
+       int i;
+
        log_debug("%s: sending vioblk", __func__);
+
+       for (i = 0; i < nr_vioblk; i++)
+               vioblk[i].vq[0].q_hva = NULL;
+
        if (atomicio(vwrite, fd, vioblk,
            nr_vioblk * sizeof(struct vioblk_dev)) !=
            nr_vioblk * sizeof(struct vioblk_dev)) {
@@ -2241,10 +2298,16 @@ vioblk_dump(int fd)
 int
 vioscsi_dump(int fd)
 {
+       unsigned int i;
+
        if (vioscsi == NULL)
                return (0);
 
        log_debug("%s: sending vioscsi", __func__);
+
+       for (i = 0; i < 3; i++)
+               vioscsi->vq[i].q_hva = NULL;
+
        if (atomicio(vwrite, fd, vioscsi, sizeof(struct vioscsi_dev)) !=
            sizeof(struct vioscsi_dev)) {
                log_warnx("%s: error writing vioscsi to fd", __func__);