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* [dpdk-dev] [PATCH] vfio: support iommu group zero
@ 2015-12-09 17:55 Stephen Hemminger
  2015-12-09 21:12 ` Thomas Monjalon
  2015-12-10  9:57 ` Burakov, Anatoly
  0 siblings, 2 replies; 12+ messages in thread
From: Stephen Hemminger @ 2015-12-09 17:55 UTC (permalink / raw)
  To: dev

The current implementation of VFIO will not with the new no-IOMMU mode
in 4.4 kernel. The original code assumed that IOMMU group zero would
never be used. Group numbers are assigned starting at zero, and up
until now the group numbers came from the hardware which is likely
to use group 0 for system devices that are not used with DPDK.

The fix is to allow 0 as a valid group and rearrange code
to split the return value from the group value.

Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
---
Why was this ignored? It was originally sent on 26 Oct 15 back
when IOMMU discussion was lively.

 lib/librte_eal/linuxapp/eal/eal_pci_vfio.c | 22 +++++++++++-----------
 1 file changed, 11 insertions(+), 11 deletions(-)

diff --git a/lib/librte_eal/linuxapp/eal/eal_pci_vfio.c b/lib/librte_eal/linuxapp/eal/eal_pci_vfio.c
index 0e6c48a..74f91ba 100644
--- a/lib/librte_eal/linuxapp/eal/eal_pci_vfio.c
+++ b/lib/librte_eal/linuxapp/eal/eal_pci_vfio.c
@@ -499,14 +499,15 @@ pci_vfio_get_group_fd(int iommu_group_no)
 }
 
 /* parse IOMMU group number for a PCI device
- * returns -1 for errors, 0 for non-existent group */
+ * returns 1 on success, -1 for errors, 0 for non-existent group
+ */
 static int
-pci_vfio_get_group_no(const char *pci_addr)
+pci_vfio_get_group_no(const char *pci_addr, int *iommu_group_no)
 {
 	char linkname[PATH_MAX];
 	char filename[PATH_MAX];
 	char *tok[16], *group_tok, *end;
-	int ret, iommu_group_no;
+	int ret;
 
 	memset(linkname, 0, sizeof(linkname));
 	memset(filename, 0, sizeof(filename));
@@ -533,13 +534,13 @@ pci_vfio_get_group_no(const char *pci_addr)
 	errno = 0;
 	group_tok = tok[ret - 1];
 	end = group_tok;
-	iommu_group_no = strtol(group_tok, &end, 10);
+	*iommu_group_no = strtol(group_tok, &end, 10);
 	if ((end != group_tok && *end != '\0') || errno != 0) {
 		RTE_LOG(ERR, EAL, "  %s error parsing IOMMU number!\n", pci_addr);
 		return -1;
 	}
 
-	return iommu_group_no;
+	return 1;
 }
 
 static void
@@ -581,16 +582,15 @@ pci_vfio_map_resource(struct rte_pci_device *dev)
 			loc->domain, loc->bus, loc->devid, loc->function);
 
 	/* get group number */
-	iommu_group_no = pci_vfio_get_group_no(pci_addr);
-
-	/* if 0, group doesn't exist */
-	if (iommu_group_no == 0) {
+	ret = pci_vfio_get_group_no(pci_addr, &iommu_group_no);
+	if (ret == 0) {
 		RTE_LOG(WARNING, EAL, "  %s not managed by VFIO driver, skipping\n",
-				pci_addr);
+			pci_addr);
 		return 1;
 	}
+
 	/* if negative, something failed */
-	else if (iommu_group_no < 0)
+	if (ret < 0)
 		return -1;
 
 	/* get the actual group fd */
-- 
2.1.4

^ permalink raw reply	[flat|nested] 12+ messages in thread
* [dpdk-dev] [PATCH] vfio: support iommu group zero
@ 2015-10-27  2:34 Stephen Hemminger
  0 siblings, 0 replies; 12+ messages in thread
From: Stephen Hemminger @ 2015-10-27  2:34 UTC (permalink / raw)
  To: dev; +Cc: alex.williamson

From: Stephen Hemminger <stephen@networkplumber.org>

The implementation of VFIO is broken on some platforms and if using
the proposed VFIO without IOMMU patch.  IOMMU group zero is a valid value.

Change code to split the return value from the group value.

Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
---
 lib/librte_eal/linuxapp/eal/eal_pci_vfio.c | 22 +++++++++++-----------
 1 file changed, 11 insertions(+), 11 deletions(-)

diff --git a/lib/librte_eal/linuxapp/eal/eal_pci_vfio.c b/lib/librte_eal/linuxapp/eal/eal_pci_vfio.c
index 0e6c48a..74f91ba 100644
--- a/lib/librte_eal/linuxapp/eal/eal_pci_vfio.c
+++ b/lib/librte_eal/linuxapp/eal/eal_pci_vfio.c
@@ -499,14 +499,15 @@ pci_vfio_get_group_fd(int iommu_group_no)
 }
 
 /* parse IOMMU group number for a PCI device
- * returns -1 for errors, 0 for non-existent group */
+ * returns 1 on success, -1 for errors, 0 for non-existent group
+ */
 static int
-pci_vfio_get_group_no(const char *pci_addr)
+pci_vfio_get_group_no(const char *pci_addr, int *iommu_group_no)
 {
 	char linkname[PATH_MAX];
 	char filename[PATH_MAX];
 	char *tok[16], *group_tok, *end;
-	int ret, iommu_group_no;
+	int ret;
 
 	memset(linkname, 0, sizeof(linkname));
 	memset(filename, 0, sizeof(filename));
@@ -533,13 +534,13 @@ pci_vfio_get_group_no(const char *pci_addr)
 	errno = 0;
 	group_tok = tok[ret - 1];
 	end = group_tok;
-	iommu_group_no = strtol(group_tok, &end, 10);
+	*iommu_group_no = strtol(group_tok, &end, 10);
 	if ((end != group_tok && *end != '\0') || errno != 0) {
 		RTE_LOG(ERR, EAL, "  %s error parsing IOMMU number!\n", pci_addr);
 		return -1;
 	}
 
-	return iommu_group_no;
+	return 1;
 }
 
 static void
@@ -581,16 +582,15 @@ pci_vfio_map_resource(struct rte_pci_device *dev)
 			loc->domain, loc->bus, loc->devid, loc->function);
 
 	/* get group number */
-	iommu_group_no = pci_vfio_get_group_no(pci_addr);
-
-	/* if 0, group doesn't exist */
-	if (iommu_group_no == 0) {
+	ret = pci_vfio_get_group_no(pci_addr, &iommu_group_no);
+	if (ret == 0) {
 		RTE_LOG(WARNING, EAL, "  %s not managed by VFIO driver, skipping\n",
-				pci_addr);
+			pci_addr);
 		return 1;
 	}
+
 	/* if negative, something failed */
-	else if (iommu_group_no < 0)
+	if (ret < 0)
 		return -1;
 
 	/* get the actual group fd */
-- 
2.1.4

^ permalink raw reply	[flat|nested] 12+ messages in thread
end of thread, other threads:[~2015-12-10 20:31 UTC | newest]

Thread overview: 12+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2015-12-09 17:55 [dpdk-dev] [PATCH] vfio: support iommu group zero Stephen Hemminger
2015-12-09 21:12 ` Thomas Monjalon
2015-12-09 21:51   ` Stephen Hemminger
2015-12-09 21:58   ` Stephen Hemminger
2015-12-09 22:49     ` Thomas Monjalon
2015-12-09 23:12       ` Stephen Hemminger
2015-12-09 23:22         ` Alex Williamson
2015-12-10  0:52           ` Stephen Hemminger
2015-12-10  1:52             ` Alex Williamson
2015-12-10  9:57 ` Burakov, Anatoly
2015-12-10 20:30   ` Thomas Monjalon
  -- strict thread matches above, loose matches on Subject: below --
2015-10-27  2:34 Stephen Hemminger

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