public inbox for passt-dev@passt.top
 help / color / mirror / code / Atom feed
From: Laurent Vivier <lvivier@redhat.com>
To: passt-dev@passt.top
Cc: Laurent Vivier <lvivier@redhat.com>
Subject: [PATCH v3 1/4] packet: replace struct desc by struct iovec
Date: Thu, 15 Aug 2024 17:50:20 +0200	[thread overview]
Message-ID: <20240815155024.827956-2-lvivier@redhat.com> (raw)
In-Reply-To: <20240815155024.827956-1-lvivier@redhat.com>

To be able to manage buffers inside a shared memory provided
by a VM via a vhost-user interface, we cannot rely on the fact
that buffers are located in a pre-defined memory area and use
a base address and a 32bit offset to address them.

We need a 64bit address, so replace struct desc by struct iovec
and update range checking.

Signed-off-by: Laurent Vivier <lvivier@redhat.com>
---
 packet.c | 80 ++++++++++++++++++++++++++++++--------------------------
 packet.h | 14 ++--------
 2 files changed, 45 insertions(+), 49 deletions(-)

diff --git a/packet.c b/packet.c
index ccfc84607709..37489961a37e 100644
--- a/packet.c
+++ b/packet.c
@@ -22,6 +22,35 @@
 #include "util.h"
 #include "log.h"
 
+/**
+ * packet_check_range() - Check if a packet memory range is valid
+ * @p:		Packet pool
+ * @offset:	Offset of data range in packet descriptor
+ * @len:	Length of desired data range
+ * @start:	Start of the packet descriptor
+ * @func:	For tracing: name of calling function
+ * @line:	For tracing: caller line of function call
+ *
+ * Return: 0 if the range is valid, -1 otherwise
+ */
+static int packet_check_range(const struct pool *p, size_t offset, size_t len,
+			      const char *start, const char *func, int line)
+{
+	if (start < p->buf) {
+		trace("packet start %p before buffer start %p, "
+		      "%s:%i", (void *)start, (void *)p->buf, func, line);
+		return -1;
+	}
+
+	if (start + len + offset > p->buf + p->buf_size) {
+		trace("packet offset plus length %lu from size %lu, "
+		      "%s:%i", start - p->buf + len + offset,
+		      p->buf_size, func, line);
+		return -1;
+	}
+
+	return 0;
+}
 /**
  * packet_add_do() - Add data as packet descriptor to given pool
  * @p:		Existing pool
@@ -41,34 +70,16 @@ void packet_add_do(struct pool *p, size_t len, const char *start,
 		return;
 	}
 
-	if (start < p->buf) {
-		trace("add packet start %p before buffer start %p, %s:%i",
-		      (void *)start, (void *)p->buf, func, line);
+	if (packet_check_range(p, 0, len, start, func, line))
 		return;
-	}
-
-	if (start + len > p->buf + p->buf_size) {
-		trace("add packet start %p, length: %zu, buffer end %p, %s:%i",
-		      (void *)start, len, (void *)(p->buf + p->buf_size),
-		      func, line);
-		return;
-	}
 
 	if (len > UINT16_MAX) {
 		trace("add packet length %zu, %s:%i", len, func, line);
 		return;
 	}
 
-#if UINTPTR_MAX == UINT64_MAX
-	if ((uintptr_t)start - (uintptr_t)p->buf > UINT32_MAX) {
-		trace("add packet start %p, buffer start %p, %s:%i",
-		      (void *)start, (void *)p->buf, func, line);
-		return;
-	}
-#endif
-
-	p->pkt[idx].offset = start - p->buf;
-	p->pkt[idx].len = len;
+	p->pkt[idx].iov_base = (void *)start;
+	p->pkt[idx].iov_len = len;
 
 	p->count++;
 }
@@ -96,36 +107,31 @@ void *packet_get_do(const struct pool *p, size_t idx, size_t offset,
 		return NULL;
 	}
 
-	if (len > UINT16_MAX || len + offset > UINT32_MAX) {
+	if (len > UINT16_MAX) {
 		if (func) {
-			trace("packet data length %zu, offset %zu, %s:%i",
-			      len, offset, func, line);
+			trace("packet data length %zu, %s:%i",
+			      len, func, line);
 		}
 		return NULL;
 	}
 
-	if (p->pkt[idx].offset + len + offset > p->buf_size) {
+	if (len + offset > p->pkt[idx].iov_len) {
 		if (func) {
-			trace("packet offset plus length %zu from size %zu, "
-			      "%s:%i", p->pkt[idx].offset + len + offset,
-			      p->buf_size, func, line);
+			trace("data length %zu, offset %zu from length %zu, "
+			      "%s:%i", len, offset, p->pkt[idx].iov_len,
+			      func, line);
 		}
 		return NULL;
 	}
 
-	if (len + offset > p->pkt[idx].len) {
-		if (func) {
-			trace("data length %zu, offset %zu from length %u, "
-			      "%s:%i", len, offset, p->pkt[idx].len,
-			      func, line);
-		}
+	if (packet_check_range(p, offset, len, p->pkt[idx].iov_base,
+			       func, line))
 		return NULL;
-	}
 
 	if (left)
-		*left = p->pkt[idx].len - offset - len;
+		*left = p->pkt[idx].iov_len - offset - len;
 
-	return p->buf + p->pkt[idx].offset + offset;
+	return (char *)p->pkt[idx].iov_base + offset;
 }
 
 /**
diff --git a/packet.h b/packet.h
index a784b07bbed5..8377dcf678bb 100644
--- a/packet.h
+++ b/packet.h
@@ -6,16 +6,6 @@
 #ifndef PACKET_H
 #define PACKET_H
 
-/**
- * struct desc - Generic offset-based descriptor within buffer
- * @offset:	Offset of descriptor relative to buffer start, 32-bit limit
- * @len:	Length of descriptor, host order, 16-bit limit
- */
-struct desc {
-	uint32_t offset;
-	uint16_t len;
-};
-
 /**
  * struct pool - Generic pool of packets stored in a buffer
  * @buf:	Buffer storing packet descriptors
@@ -29,7 +19,7 @@ struct pool {
 	size_t buf_size;
 	size_t size;
 	size_t count;
-	struct desc pkt[1];
+	struct iovec pkt[1];
 };
 
 void packet_add_do(struct pool *p, size_t len, const char *start,
@@ -54,7 +44,7 @@ struct _name ## _t {							\
 	size_t buf_size;						\
 	size_t size;							\
 	size_t count;							\
-	struct desc pkt[_size];						\
+	struct iovec pkt[_size];					\
 }
 
 #define PACKET_POOL_INIT_NOCAST(_size, _buf, _buf_size)			\
-- 
@@ -6,16 +6,6 @@
 #ifndef PACKET_H
 #define PACKET_H
 
-/**
- * struct desc - Generic offset-based descriptor within buffer
- * @offset:	Offset of descriptor relative to buffer start, 32-bit limit
- * @len:	Length of descriptor, host order, 16-bit limit
- */
-struct desc {
-	uint32_t offset;
-	uint16_t len;
-};
-
 /**
  * struct pool - Generic pool of packets stored in a buffer
  * @buf:	Buffer storing packet descriptors
@@ -29,7 +19,7 @@ struct pool {
 	size_t buf_size;
 	size_t size;
 	size_t count;
-	struct desc pkt[1];
+	struct iovec pkt[1];
 };
 
 void packet_add_do(struct pool *p, size_t len, const char *start,
@@ -54,7 +44,7 @@ struct _name ## _t {							\
 	size_t buf_size;						\
 	size_t size;							\
 	size_t count;							\
-	struct desc pkt[_size];						\
+	struct iovec pkt[_size];					\
 }
 
 #define PACKET_POOL_INIT_NOCAST(_size, _buf, _buf_size)			\
-- 
2.45.2


  reply	other threads:[~2024-08-15 15:50 UTC|newest]

Thread overview: 22+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-08-15 15:50 [PATCH v3 0/4] Add vhost-user support to passt. (part 3) Laurent Vivier
2024-08-15 15:50 ` Laurent Vivier [this message]
2024-08-20  0:27   ` [PATCH v3 1/4] packet: replace struct desc by struct iovec David Gibson
2024-08-15 15:50 ` [PATCH v3 2/4] vhost-user: introduce virtio API Laurent Vivier
2024-08-20  1:00   ` David Gibson
2024-08-22 22:14   ` Stefano Brivio
2024-08-15 15:50 ` [PATCH v3 3/4] vhost-user: introduce vhost-user API Laurent Vivier
2024-08-22 22:14   ` Stefano Brivio
2024-08-26  5:27     ` David Gibson
2024-08-26  7:55       ` Stefano Brivio
2024-08-26  9:53         ` David Gibson
2024-08-26  5:26   ` David Gibson
2024-08-26 22:14     ` Stefano Brivio
2024-08-27  4:42       ` David Gibson
2024-09-05  9:58     ` Laurent Vivier
2024-08-15 15:50 ` [PATCH v3 4/4] vhost-user: add vhost-user Laurent Vivier
2024-08-22  9:59   ` Stefano Brivio
2024-08-22 22:14   ` Stefano Brivio
2024-08-23 12:32   ` Stefano Brivio
2024-08-20 22:41 ` [PATCH v3 0/4] Add vhost-user support to passt. (part 3) Stefano Brivio
2024-08-22 16:53   ` Stefano Brivio
2024-08-23 12:32     ` Stefano Brivio

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20240815155024.827956-2-lvivier@redhat.com \
    --to=lvivier@redhat.com \
    --cc=passt-dev@passt.top \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
Code repositories for project(s) associated with this public inbox

	https://passt.top/passt

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for IMAP folder(s).