[dpdk-dev] [PATCH v1] vhost: fix gpa to hpa conversion

[dpdk-dev] [PATCH v1] vhost: fix gpa to hpa conversion

[Patrick Fu]

gpa_to_hpa() function almost always fails due to the wrong setup of
the b tree search key. Since there has been already a similar function
gpa_to_first_hap() available in the vhost, instead of fixing the
issue in its original logic, gpa_to_hpa() function is rewritten to be
a wrapper of the gpa_to_first_hpa() to avoid code redundancy.

Fixes: e246896178e6 ("vhost: get guest/host physical address mappings")
Fixes: faa9867c4da2 ("vhost: use binary search in address conversion")

Signed-off-by: Patrick Fu <patrick.fu@intel.com>
---
 lib/librte_vhost/vhost.h | 43 ++++++++++------------------------------
 1 file changed, 11 insertions(+), 32 deletions(-)

diff --git a/lib/librte_vhost/vhost.h b/lib/librte_vhost/vhost.h
index 75d79f80a..361c9f79b 100644
--- a/lib/librte_vhost/vhost.h
+++ b/lib/librte_vhost/vhost.h
@@ -563,38 +563,6 @@ static __rte_always_inline int guest_page_addrcmp(const void *p1,
 	return 0;
 }
 
-/* Convert guest physical address to host physical address */
-static __rte_always_inline rte_iova_t
-gpa_to_hpa(struct virtio_net *dev, uint64_t gpa, uint64_t size)
-{
-	uint32_t i;
-	struct guest_page *page;
-	struct guest_page key;
-
-	if (dev->nr_guest_pages >= VHOST_BINARY_SEARCH_THRESH) {
-		key.guest_phys_addr = gpa;
-		page = bsearch(&key, dev->guest_pages, dev->nr_guest_pages,
-			       sizeof(struct guest_page), guest_page_addrcmp);
-		if (page) {
-			if (gpa + size < page->guest_phys_addr + page->size)
-				return gpa - page->guest_phys_addr +
-					page->host_phys_addr;
-		}
-	} else {
-		for (i = 0; i < dev->nr_guest_pages; i++) {
-			page = &dev->guest_pages[i];
-
-			if (gpa >= page->guest_phys_addr &&
-			    gpa + size < page->guest_phys_addr +
-			    page->size)
-				return gpa - page->guest_phys_addr +
-				       page->host_phys_addr;
-		}
-	}
-
-	return 0;
-}
-
 static __rte_always_inline rte_iova_t
 gpa_to_first_hpa(struct virtio_net *dev, uint64_t gpa,
 	uint64_t gpa_size, uint64_t *hpa_size)
@@ -645,6 +613,17 @@ gpa_to_first_hpa(struct virtio_net *dev, uint64_t gpa,
 	return 0;
 }
 
+/* Convert guest physical address to host physical address */
+static __rte_always_inline rte_iova_t
+gpa_to_hpa(struct virtio_net *dev, uint64_t gpa, uint64_t size)
+{
+	rte_iova_t hpa;
+	uint64_t hpa_size;
+
+	hpa = gpa_to_first_hpa(dev, gpa, size, &hpa_size);
+	return hpa_size == size ? hpa : 0;
+}
+
 static __rte_always_inline uint64_t
 hva_to_gpa(struct virtio_net *dev, uint64_t vva, uint64_t len)
 {
-- 
2.18.4

[dpdk-dev] [PATCH v1] vhost: fix guest/host physical address conversion

[Patrick Fu]

gpa_to_hpa() function almost always fails due to the wrong setup of
the binary tree search key. Since there has already been a similar
function gpa_to_first_hpa() available in the vhost, instead of fixing
the issue in its original logic, gpa_to_hpa() function is rewritten to
be a wrapper of the gpa_to_first_hpa() to avoid code redundancy.

Fixes: e246896178e6 ("vhost: get guest/host physical address mappings")
Fixes: faa9867c4da2 ("vhost: use binary search in address conversion")

Signed-off-by: Patrick Fu <patrick.fu@intel.com>
---
 v2:
   - minor rewordings on commit message & title

 lib/librte_vhost/vhost.h | 43 ++++++++++------------------------------
 1 file changed, 11 insertions(+), 32 deletions(-)

diff --git a/lib/librte_vhost/vhost.h b/lib/librte_vhost/vhost.h
index 75d79f80a..361c9f79b 100644
--- a/lib/librte_vhost/vhost.h
+++ b/lib/librte_vhost/vhost.h
@@ -563,38 +563,6 @@ static __rte_always_inline int guest_page_addrcmp(const void *p1,
 	return 0;
 }
 
-/* Convert guest physical address to host physical address */
-static __rte_always_inline rte_iova_t
-gpa_to_hpa(struct virtio_net *dev, uint64_t gpa, uint64_t size)
-{
-	uint32_t i;
-	struct guest_page *page;
-	struct guest_page key;
-
-	if (dev->nr_guest_pages >= VHOST_BINARY_SEARCH_THRESH) {
-		key.guest_phys_addr = gpa;
-		page = bsearch(&key, dev->guest_pages, dev->nr_guest_pages,
-			       sizeof(struct guest_page), guest_page_addrcmp);
-		if (page) {
-			if (gpa + size < page->guest_phys_addr + page->size)
-				return gpa - page->guest_phys_addr +
-					page->host_phys_addr;
-		}
-	} else {
-		for (i = 0; i < dev->nr_guest_pages; i++) {
-			page = &dev->guest_pages[i];
-
-			if (gpa >= page->guest_phys_addr &&
-			    gpa + size < page->guest_phys_addr +
-			    page->size)
-				return gpa - page->guest_phys_addr +
-				       page->host_phys_addr;
-		}
-	}
-
-	return 0;
-}
-
 static __rte_always_inline rte_iova_t
 gpa_to_first_hpa(struct virtio_net *dev, uint64_t gpa,
 	uint64_t gpa_size, uint64_t *hpa_size)
@@ -645,6 +613,17 @@ gpa_to_first_hpa(struct virtio_net *dev, uint64_t gpa,
 	return 0;
 }
 
+/* Convert guest physical address to host physical address */
+static __rte_always_inline rte_iova_t
+gpa_to_hpa(struct virtio_net *dev, uint64_t gpa, uint64_t size)
+{
+	rte_iova_t hpa;
+	uint64_t hpa_size;
+
+	hpa = gpa_to_first_hpa(dev, gpa, size, &hpa_size);
+	return hpa_size == size ? hpa : 0;
+}
+
 static __rte_always_inline uint64_t
 hva_to_gpa(struct virtio_net *dev, uint64_t vva, uint64_t len)
 {
-- 
2.18.4

Re: [dpdk-dev] [PATCH v1] vhost: fix guest/host physical address conversion

[Maxime Coquelin]

On 10/27/20 3:06 AM, Patrick Fu wrote:
> gpa_to_hpa() function almost always fails due to the wrong setup of
> the binary tree search key. Since there has already been a similar
> function gpa_to_first_hpa() available in the vhost, instead of fixing
> the issue in its original logic, gpa_to_hpa() function is rewritten to
> be a wrapper of the gpa_to_first_hpa() to avoid code redundancy.
> 
> Fixes: e246896178e6 ("vhost: get guest/host physical address mappings")
> Fixes: faa9867c4da2 ("vhost: use binary search in address conversion")
> 
> Signed-off-by: Patrick Fu <patrick.fu@intel.com>
> ---
>  v2:
>    - minor rewordings on commit message & title
> 
>  lib/librte_vhost/vhost.h | 43 ++++++++++------------------------------
>  1 file changed, 11 insertions(+), 32 deletions(-)
> 

Reviewed-by: Maxime Coquelin <maxime.coquelin@redhat.com>

Thanks,
Maxime

Re: [dpdk-dev] [PATCH v1] vhost: fix guest/host physical address conversion

[Maxime Coquelin]

On 10/27/20 3:06 AM, Patrick Fu wrote:
> gpa_to_hpa() function almost always fails due to the wrong setup of
> the binary tree search key. Since there has already been a similar
> function gpa_to_first_hpa() available in the vhost, instead of fixing
> the issue in its original logic, gpa_to_hpa() function is rewritten to
> be a wrapper of the gpa_to_first_hpa() to avoid code redundancy.
> 
> Fixes: e246896178e6 ("vhost: get guest/host physical address mappings")
> Fixes: faa9867c4da2 ("vhost: use binary search in address conversion")
> 
> Signed-off-by: Patrick Fu <patrick.fu@intel.com>
> ---
>  v2:
>    - minor rewordings on commit message & title
> 

Applied to dpdk-next-virtio/main.

Thanks!
Maxime