[RFC V2 4/4] VFIO: Add support for SRIOV extended capablity

Ilya Lesokhin
2016-02-04T08:29:46Z

Add support for PCIE SRIOV extended capablity with following features:
1. The ability to probe SRIOV BAR sizes.
2. The ability to enable and disable sriov.

Signed-off-by: Ilya Lesokhin <ilyal@mellanox.com>
Signed-off-by: Noa Osherovich <noaos@mellanox.com>
Signed-off-by: Haggai Eran <haggaie@mellanox.com>
---
drivers/vfio/pci/vfio_pci_config.c | 169 +++++++++++++++++++++++++++++++++----
1 file changed, 152 insertions(+), 17 deletions(-)

diff --git a/drivers/vfio/pci/vfio_pci_config.c b/drivers/vfio/pci/vfio_pci_config.c
index ff75ca3..04e364f 100644
--- a/drivers/vfio/pci/vfio_pci_config.c
+++ b/drivers/vfio/pci/vfio_pci_config.c
@@ -420,6 +420,35 @@ static __le32 vfio_generate_bar_flags(struct pci_dev *pdev, int bar)
return cpu_to_le32(val);
}

+static void vfio_sriov_bar_fixup(struct vfio_pci_device *vdev,
+ int sriov_cap_start)
+{
+ struct pci_dev *pdev = vdev->pdev;
+ int i;
+ __le32 *bar;
+ u64 mask;
+
+ bar = (__le32 *)&vdev->vconfig[sriov_cap_start + PCI_SRIOV_BAR];
+
+ for (i = PCI_IOV_RESOURCES; i <= PCI_IOV_RESOURCE_END; i++, bar++) {
+ if (!pci_resource_start(pdev, i)) {
+ *bar = 0; /* Unmapped by host = unimplemented to user */
+ continue;
+ }
+
+ mask = ~(pci_iov_resource_size(pdev, i) - 1);
+
+ *bar &= cpu_to_le32((u32)mask);
+ *bar |= vfio_generate_bar_flags(pdev, i);
+
+ if (*bar & cpu_to_le32(PCI_BASE_ADDRESS_MEM_TYPE_64)) {
+ bar++;
+ *bar &= cpu_to_le32((u32)(mask >> 32));
+ i++;
+ }
+ }
+}
+
/*
* Pretend we're hardware and tweak the values of the *virtual* PCI BARs
* to reflect the hardware capabilities. This implements BAR sizing.
@@ -782,6 +811,124 @@ static int __init init_pci_ext_cap_pwr_perm(struct perm_bits *perm)
return 0;
}

+static int __init init_pci_ext_cap_sriov_perm(struct perm_bits *perm)
+{
+ int i;
+
+ if (alloc_perm_bits(perm, pci_ext_cap_length[PCI_EXT_CAP_ID_SRIOV]))
+ return -ENOMEM;
+
+ /*
+ * Virtualize the first dword of all express capabilities
+ * because it includes the next pointer. This lets us later
+ * remove capabilities from the chain if we need to.
+ */
+ p_setd(perm, 0, ALL_VIRT, NO_WRITE);
+
+ /* VF Enable - Virtualized and writable
+ * Memory Space Enable - Non-virtualized and writable
+ */
+ p_setw(perm, PCI_SRIOV_CTRL, PCI_SRIOV_CTRL_VFE,
+ PCI_SRIOV_CTRL_VFE | PCI_SRIOV_CTRL_MSE);
+
+ p_setw(perm, PCI_SRIOV_NUM_VF, (u16)ALL_VIRT, (u16)ALL_WRITE);
+ p_setw(perm, PCI_SRIOV_SUP_PGSIZE, (u16)ALL_VIRT, 0);
+
+ /* We cannot let user space application change the page size
+ * so we mark it as read only and trust the user application
+ * (e.g. qemu) to virtualize this correctly for the guest
+ */
+ p_setw(perm, PCI_SRIOV_SYS_PGSIZE, (u16)ALL_VIRT, 0);
+
+ for (i = 0; i < PCI_SRIOV_NUM_BARS; i++)
+ p_setd(perm, PCI_SRIOV_BAR + 4 * i, ALL_VIRT, ALL_WRITE);
+
+ return 0;
+}
+
+static int vfio_find_cap_start(struct vfio_pci_device *vdev, int pos)
+{
+ u8 cap;
+ int base = (pos >= PCI_CFG_SPACE_SIZE) ? PCI_CFG_SPACE_SIZE :
+ PCI_STD_HEADER_SIZEOF;
+ cap = vdev->pci_config_map[pos];
+
+ if (cap == PCI_CAP_ID_BASIC)
+ return 0;
+
+ /* XXX Can we have to abutting capabilities of the same type? */
+ while (pos - 1 >= base && vdev->pci_config_map[pos - 1] == cap)
+ pos--;
+
+ return pos;
+}
+
+static int vfio_sriov_cap_config_read(struct vfio_pci_device *vdev, int pos,
+ int count, struct perm_bits *perm,
+ int offset, __le32 *val)
+{
+ int cap_start = vfio_find_cap_start(vdev, pos);
+
+ vfio_sriov_bar_fixup(vdev, cap_start);
+ return vfio_default_config_read(vdev, pos, count, perm, offset, val);
+}
+
+static int vfio_sriov_cap_config_write(struct vfio_pci_device *vdev, int pos,
+ int count, struct perm_bits *perm,
+ int offset, __le32 val)
+{
+ int ret;
+ int cap_start = vfio_find_cap_start(vdev, pos);
+ u16 sriov_ctrl = *(u16 *)(vdev->vconfig + cap_start + PCI_SRIOV_CTRL);
+ bool cur_vf_enabled = sriov_ctrl & PCI_SRIOV_CTRL_VFE;
+ bool vf_enabled;
+
+ switch (offset) {
+ case PCI_SRIOV_NUM_VF:
+ /* Per SR-IOV spec sec 3.3.10 and 3.3.11, First VF Offset
+ * and VF Stride may change when NumVFs changes.
+ *
+ * Therefore we should pass valid writes to the hardware.
+ *
+ * Per SR-IOV spec sec 3.3.7
+ * The results are undefined if NumVFs is set to a value greater
+ * than TotalVFs.
+ * NumVFs may only be written while VF Enable is Clear.
+ * If NumVFs is written when VF Enable is Set, the results
+ * are undefined.
+
+ * Avoid passing such writes to the Hardware just in case.
+ */
+ if (cur_vf_enabled ||
+ val > pci_sriov_get_totalvfs(vdev->pdev))
+ return count;
+
+ pci_iov_set_numvfs(vdev->pdev, val);
+ break;
+
+ case PCI_SRIOV_CTRL:
+ vf_enabled = val & PCI_SRIOV_CTRL_VFE;
+
+ if (!cur_vf_enabled && vf_enabled) {
+ u16 num_vfs = *(u16 *)(vdev->vconfig +
+ cap_start +
+ PCI_SRIOV_NUM_VF);
+ ret = pci_enable_sriov(vdev->pdev, num_vfs);
+ if (ret)
+ return count;
+ } else if (cur_vf_enabled && !vf_enabled) {
+ pci_disable_sriov(vdev->pdev);
+ }
+ break;
+
+ default:
+ break;
+ }
+
+ return vfio_default_config_write(vdev, pos, count, perm,
+ offset, val);
+}
+
/*
* Initialize the shared permission tables
*/
@@ -796,6 +943,7 @@ void vfio_pci_uninit_perm_bits(void)

free_perm_bits(&ecap_perms[PCI_EXT_CAP_ID_ERR]);
free_perm_bits(&ecap_perms[PCI_EXT_CAP_ID_PWR]);
+ free_perm_bits(&ecap_perms[PCI_EXT_CAP_ID_SRIOV]);
}

int __init vfio_pci_init_perm_bits(void)
@@ -818,29 +966,16 @@ int __init vfio_pci_init_perm_bits(void)
ret |= init_pci_ext_cap_pwr_perm(&ecap_perms[PCI_EXT_CAP_ID_PWR]);
ecap_perms[PCI_EXT_CAP_ID_VNDR].writefn = vfio_raw_config_write;

+ ret |= init_pci_ext_cap_sriov_perm(&ecap_perms[PCI_EXT_CAP_ID_SRIOV]);
+ ecap_perms[PCI_EXT_CAP_ID_SRIOV].readfn = vfio_sriov_cap_config_read;
+ ecap_perms[PCI_EXT_CAP_ID_SRIOV].writefn = vfio_sriov_cap_config_write;
+
if (ret)
vfio_pci_uninit_perm_bits();

return ret;
}

-static int vfio_find_cap_start(struct vfio_pci_device *vdev, int pos)
-{
- u8 cap;
- int base = (pos >= PCI_CFG_SPACE_SIZE) ? PCI_CFG_SPACE_SIZE :
- PCI_STD_HEADER_SIZEOF;
- cap = vdev->pci_config_map[pos];
-
- if (cap == PCI_CAP_ID_BASIC)
- return 0;
-
- /* XXX Can we have to abutting capabilities of the same type? */
- while (pos - 1 >= base && vdev->pci_config_map[pos - 1] == cap)
- pos--;
-
- return pos;
-}
-
static int vfio_msi_config_read(struct vfio_pci_device *vdev, int pos,
int count, struct perm_bits *perm,
int offset, __le32 *val)
--
1.8.3.1