On 4/9/25 15:48, John Levon wrote:
Add these helpers that access config space and return an -errno style
return.
Signed-off-by: John Levon <john.le...@nutanix.com>
---
hw/vfio/pci.c | 134 ++++++++++++++++++++++++++++++++++----------------
1 file changed, 91 insertions(+), 43 deletions(-)
diff --git a/hw/vfio/pci.c b/hw/vfio/pci.c
index ddeee33aa9..c3842d2f8d 100644
--- a/hw/vfio/pci.c
+++ b/hw/vfio/pci.c
@@ -964,6 +964,28 @@ static void vfio_pci_load_rom(VFIOPCIDevice *vdev)
}
}
+/* "Raw" read of underlying config space. */
+static int vfio_pci_config_space_read(VFIOPCIDevice *vdev, off_t offset,
+ uint32_t size, void *data)
+{
+ ssize_t ret;
+
+ ret = pread(vdev->vbasedev.fd, data, size, vdev->config_offset + offset);
+
+ return ret < 0 ? -errno : (int)ret;
+}
+
+/* "Raw" write of underlying config space. */
+static int vfio_pci_config_space_write(VFIOPCIDevice *vdev, off_t offset,
+ uint32_t size, void *data)
+{
+ ssize_t ret;
+
+ ret = pwrite(vdev->vbasedev.fd, data, size, vdev->config_offset + offset);
+
+ return ret < 0 ? -errno : (int)ret;
+}
+
static uint64_t vfio_rom_read(void *opaque, hwaddr addr, unsigned size)
{
VFIOPCIDevice *vdev = opaque;
@@ -1016,10 +1038,9 @@ static const MemoryRegionOps vfio_rom_ops = {
static void vfio_pci_size_rom(VFIOPCIDevice *vdev)
{
+ VFIODevice *vbasedev = &vdev->vbasedev;
uint32_t orig, size = cpu_to_le32((uint32_t)PCI_ROM_ADDRESS_MASK);
- off_t offset = vdev->config_offset + PCI_ROM_ADDRESS;
char *name;
- int fd = vdev->vbasedev.fd;
if (vdev->pdev.romfile || !vdev->pdev.rom_bar) {
/* Since pci handles romfile, just print a message and return */
@@ -1036,11 +1057,12 @@ static void vfio_pci_size_rom(VFIOPCIDevice *vdev)
* Use the same size ROM BAR as the physical device. The contents
* will get filled in later when the guest tries to read it.
*/
- if (pread(fd, &orig, 4, offset) != 4 ||
- pwrite(fd, &size, 4, offset) != 4 ||
- pread(fd, &size, 4, offset) != 4 ||
- pwrite(fd, &orig, 4, offset) != 4) {
- error_report("%s(%s) failed: %m", __func__, vdev->vbasedev.name);
+ if (vfio_pci_config_space_read(vdev, PCI_ROM_ADDRESS, 4, &orig) != 4 ||
+ vfio_pci_config_space_write(vdev, PCI_ROM_ADDRESS, 4, &size) != 4 ||
+ vfio_pci_config_space_read(vdev, PCI_ROM_ADDRESS, 4, &size) != 4 ||
+ vfio_pci_config_space_write(vdev, PCI_ROM_ADDRESS, 4, &orig) != 4) {
+
+ error_report("%s(%s) ROM access failed", __func__, vbasedev->name);
return;
}
@@ -1220,6 +1242,7 @@ static void vfio_sub_page_bar_update_mapping(PCIDevice *pdev, int bar)
uint32_t vfio_pci_read_config(PCIDevice *pdev, uint32_t addr, int len)
{
VFIOPCIDevice *vdev = VFIO_PCI_BASE(pdev);
+ VFIODevice *vbasedev = &vdev->vbasedev;
uint32_t emu_bits = 0, emu_val = 0, phys_val = 0, val;
memcpy(&emu_bits, vdev->emulated_config_bits + addr, len);
@@ -1232,12 +1255,13 @@ uint32_t vfio_pci_read_config(PCIDevice *pdev, uint32_t
addr, int len)
if (~emu_bits & (0xffffffffU >> (32 - len * 8))) {
ssize_t ret;
- ret = pread(vdev->vbasedev.fd, &phys_val, len,
- vdev->config_offset + addr);
+ ret = vfio_pci_config_space_read(vdev, addr, len, &phys_val);
if (ret != len) {
- error_report("%s(%s, 0x%x, 0x%x) failed: %m",
- __func__, vdev->vbasedev.name, addr, len);
- return -errno;
+ const char *err = ret < 0 ? strerror(-ret) : "short read";
These "short read/write" messages, here and below, are a bit invasive
in the code but they are interesting to keep. I wonder if we could
improve readability with some helper.
+
+ error_report("%s(%s, 0x%x, 0x%x) failed: %s",
+ __func__, vbasedev->name, addr, len, err);
+ return -1;
-1 (all ones) seems more correct than returning -errno as before.
}
phys_val = le32_to_cpu(phys_val);
}
@@ -1253,15 +1277,19 @@ void vfio_pci_write_config(PCIDevice *pdev,
uint32_t addr, uint32_t val, int len)
{
VFIOPCIDevice *vdev = VFIO_PCI_BASE(pdev);
+ VFIODevice *vbasedev = &vdev->vbasedev;
uint32_t val_le = cpu_to_le32(val);
+ int ret;
trace_vfio_pci_write_config(vdev->vbasedev.name, addr, val, len);
/* Write everything to VFIO, let it filter out what we can't write */
- if (pwrite(vdev->vbasedev.fd, &val_le, len, vdev->config_offset + addr)
- != len) {
- error_report("%s(%s, 0x%x, 0x%x, 0x%x) failed: %m",
- __func__, vdev->vbasedev.name, addr, val, len);
+ ret = vfio_pci_config_space_write(vdev, addr, len, &val_le);
+ if (ret != len) {
+ const char *err = ret < 0 ? strerror(-ret) : "short write";
+
+ error_report("%s(%s, 0x%x, 0x%x, 0x%x) failed: %s",
+ __func__, vbasedev->name, addr, val, len, err);
}
/* MSI/MSI-X Enabling/Disabling */
@@ -1349,9 +1377,12 @@ static bool vfio_msi_setup(VFIOPCIDevice *vdev, int pos,
Error **errp)
int ret, entries;
Error *err = NULL;
- if (pread(vdev->vbasedev.fd, &ctrl, sizeof(ctrl),
- vdev->config_offset + pos + PCI_CAP_FLAGS) != sizeof(ctrl)) {
- error_setg_errno(errp, errno, "failed reading MSI PCI_CAP_FLAGS");
+ ret = vfio_pci_config_space_read(vdev, pos + PCI_CAP_FLAGS,
+ sizeof(ctrl), &ctrl);
+ if (ret != sizeof(ctrl)) {
+ const char *errmsg = ret < 0 ? strerror(-ret) : "short read";
+
+ error_setg(errp, "failed reading MSI PCI_CAP_FLAGS: %s", errmsg);
return false;
}
ctrl = le16_to_cpu(ctrl);
@@ -1558,30 +1589,39 @@ static bool vfio_msix_early_setup(VFIOPCIDevice *vdev,
Error **errp)
uint8_t pos;
uint16_t ctrl;
uint32_t table, pba;
- int ret, fd = vdev->vbasedev.fd;
struct vfio_irq_info irq_info;
VFIOMSIXInfo *msix;
+ int ret;
pos = pci_find_capability(&vdev->pdev, PCI_CAP_ID_MSIX);
if (!pos) {
return true;
}
- if (pread(fd, &ctrl, sizeof(ctrl),
- vdev->config_offset + pos + PCI_MSIX_FLAGS) != sizeof(ctrl)) {
- error_setg_errno(errp, errno, "failed to read PCI MSIX FLAGS");
+ ret = vfio_pci_config_space_read(vdev, pos + PCI_MSIX_FLAGS,
+ sizeof(ctrl), &ctrl);
+ if (ret != sizeof(ctrl)) {
+ const char *err = ret < 0 ? strerror(-ret) : "short read";
+
+ error_setg(errp, "failed to read PCI MSIX FLAGS: %s", err);
return false;
}
- if (pread(fd, &table, sizeof(table),
- vdev->config_offset + pos + PCI_MSIX_TABLE) != sizeof(table)) {
- error_setg_errno(errp, errno, "failed to read PCI MSIX TABLE");
+ ret = vfio_pci_config_space_read(vdev, pos + PCI_MSIX_TABLE,
+ sizeof(table), &table);
+ if (ret != sizeof(table)) {
+ const char *err = ret < 0 ? strerror(-ret) : "short read";
+
+ error_setg(errp, "failed to read PCI MSIX TABLE: %s", err);
return false;
}
- if (pread(fd, &pba, sizeof(pba),
- vdev->config_offset + pos + PCI_MSIX_PBA) != sizeof(pba)) {
- error_setg_errno(errp, errno, "failed to read PCI MSIX PBA");
+ ret = vfio_pci_config_space_read(vdev, pos + PCI_MSIX_PBA,
+ sizeof(pba), &pba);
+ if (ret != sizeof(pba)) {
+ const char *err = ret < 0 ? strerror(-ret) : "short read";
+
+ error_setg(errp, "failed to read PCI MSIX PBA: %s", err);
return false;
}
@@ -1741,10 +1781,12 @@ static void vfio_bar_prepare(VFIOPCIDevice *vdev, int nr)
}
/* Determine what type of BAR this is for registration */
- ret = pread(vdev->vbasedev.fd, &pci_bar, sizeof(pci_bar),
- vdev->config_offset + PCI_BASE_ADDRESS_0 + (4 * nr));
+ ret = vfio_pci_config_space_read(vdev, PCI_BASE_ADDRESS_0 + (4 * nr),
+ sizeof(pci_bar), &pci_bar);
if (ret != sizeof(pci_bar)) {
- error_report("vfio: Failed to read BAR %d (%m)", nr);
+ const char *err = ret < 0 ? strerror(-ret) : "short read";
+
+ error_report("vfio: Failed to read BAR %d: %s", nr, err);
return;
}
@@ -2448,21 +2490,25 @@ void vfio_pci_pre_reset(VFIOPCIDevice *vdev)
void vfio_pci_post_reset(VFIOPCIDevice *vdev)
{
+ VFIODevice *vbasedev = &vdev->vbasedev;
Error *err = NULL;
- int nr;
+ int ret, nr;
if (!vfio_intx_enable(vdev, &err)) {
error_reportf_err(err, VFIO_MSG_PREFIX, vdev->vbasedev.name);
}
for (nr = 0; nr < PCI_NUM_REGIONS - 1; ++nr) {
- off_t addr = vdev->config_offset + PCI_BASE_ADDRESS_0 + (4 * nr);
+ off_t addr = PCI_BASE_ADDRESS_0 + (4 * nr);
uint32_t val = 0;
uint32_t len = sizeof(val);
- if (pwrite(vdev->vbasedev.fd, &val, len, addr) != len) {
- error_report("%s(%s) reset bar %d failed: %m", __func__,
- vdev->vbasedev.name, nr);
+ ret = vfio_pci_config_space_write(vdev, addr, len, &val);
+ if (ret != len) {
+ const char *errmsg = ret < 0 ? strerror(-ret) : "short write";
+
+ error_report("%s(%s) reset bar %d failed: %s", __func__,
+ vbasedev->name, nr, errmsg);
}
}
@@ -3099,6 +3145,7 @@ static void vfio_realize(PCIDevice *pdev, Error **errp)
int i, ret;
char uuid[UUID_STR_LEN];
g_autofree char *name = NULL;
+ size_t config_space_size;
why not use uint32_t ?
Thanks,
C.
if (vbasedev->fd < 0 && !vbasedev->sysfsdev) {
if (!(~vdev->host.domain || ~vdev->host.bus ||
@@ -3153,13 +3200,14 @@ static void vfio_realize(PCIDevice *pdev, Error **errp)
goto error;
}
+ config_space_size = MIN(pci_config_size(&vdev->pdev), vdev->config_size);
+
/* Get a copy of config space */
- ret = pread(vbasedev->fd, vdev->pdev.config,
- MIN(pci_config_size(&vdev->pdev), vdev->config_size),
- vdev->config_offset);
- if (ret < (int)MIN(pci_config_size(&vdev->pdev), vdev->config_size)) {
- ret = ret < 0 ? -errno : -EFAULT;
- error_setg_errno(errp, -ret, "failed to read device config space");
+ ret = vfio_pci_config_space_read(vdev, 0, config_space_size,
+ vdev->pdev.config);
+ if (ret < (int)config_space_size) {
+ ret = ret < 0 ? -ret : EFAULT;
+ error_setg_errno(errp, ret, "failed to read device config space");
goto error;
}
