[dpdk-dev] [PATCH 2/2] eal/bsd: fix the read operation on PCI configuration space

[Tiwei Bie <tiwei.bie@intel.com>]

Some drivers (such as virtio) may need to read more than 4 bytes
data from PCI configuration space via rte_eal_pci_read_config().
But it will return with an error on FreeBSD when the expected
data length is bigger than the size of pi.pi_data whose type is
u_int32_t. This patch removes this limitation.

Fixes: 632b2d1deeed ("eal: provide functions to access PCI config")
Cc: stable@dpdk.org

Signed-off-by: Tiwei Bie <tiwei.bie@intel.com>
---
 lib/librte_eal/bsdapp/eal/eal_pci.c | 22 +++++++++++++---------
 1 file changed, 13 insertions(+), 9 deletions(-)

diff --git a/lib/librte_eal/bsdapp/eal/eal_pci.c b/lib/librte_eal/bsdapp/eal/eal_pci.c
index 59ceb7665..e321461d8 100644
--- a/lib/librte_eal/bsdapp/eal/eal_pci.c
+++ b/lib/librte_eal/bsdapp/eal/eal_pci.c
@@ -459,6 +459,7 @@ int rte_pci_read_config(const struct rte_pci_device *dev,
 		void *buf, size_t len, off_t offset)
 {
 	int fd = -1;
+	int size;
 	struct pci_io pi = {
 		.pi_sel = {
 			.pc_domain = dev->addr.domain,
@@ -467,25 +468,28 @@ int rte_pci_read_config(const struct rte_pci_device *dev,
 			.pc_func = dev->addr.function,
 		},
 		.pi_reg = offset,
-		.pi_width = len,
 	};
 
-	if (len == 3 || len > sizeof(pi.pi_data)) {
-		RTE_LOG(ERR, EAL, "%s(): invalid pci read length\n", __func__);
-		goto error;
-	}
-
 	fd = open("/dev/pci", O_RDWR);
 	if (fd < 0) {
 		RTE_LOG(ERR, EAL, "%s(): error opening /dev/pci\n", __func__);
 		goto error;
 	}
 
-	if (ioctl(fd, PCIOCREAD, &pi) < 0)
-		goto error;
+	while (len > 0) {
+		size = (len >= 4) ? 4 : ((len >= 2) ? 2 : 1);
+		pi.pi_width = size;
+
+		if (ioctl(fd, PCIOCREAD, &pi) < 0)
+			goto error;
+		memcpy(buf, &pi.pi_data, size);
+
+		buf = (char *)buf + size;
+		pi.pi_reg += size;
+		len -= size;
+	}
 	close(fd);
 
-	memcpy(buf, &pi.pi_data, len);
 	return 0;
 
  error:
-- 
2.12.1