Re: [PATCH [repost]] block/blkio: Don't assume size_t is 64 bit
On Tue, Jan 30, 2024 at 12:19:37PM +, Richard W.M. Jones wrote:
> On Tue, Jan 30, 2024 at 01:04:46PM +0100, Kevin Wolf wrote:
> > Am 30.01.2024 um 11:30 hat Richard W.M. Jones geschrieben:
> > > On Tue, Jan 30, 2024 at 09:51:59AM +0100, Kevin Wolf wrote:
> > > > Am 29.01.2024 um 19:53 hat Richard W.M. Jones geschrieben:
> > > > > With GCC 14 the code failed to compile on i686 (and was wrong for any
> > > > > version of GCC):
> > > > >
> > > > > ../block/blkio.c: In function ‘blkio_file_open’:
> > > > > ../block/blkio.c:857:28: error: passing argument 3 of
> > > > > ‘blkio_get_uint64’ from incompatible pointer type
> > > > > [-Wincompatible-pointer-types]
> > > > > 857 |>mem_region_alignment);
> > > > > |^~~~
> > > > > ||
> > > > > |size_t * {aka unsigned int *}
> > > > > In file included from ../block/blkio.c:12:
> > > > > /usr/include/blkio.h:49:67: note: expected ‘uint64_t *’ {aka ‘long
> > > > > long unsigned int *’} but argument is of type ‘size_t *’ {aka
> > > > > ‘unsigned int *’}
> > > > >49 | int blkio_get_uint64(struct blkio *b, const char *name,
> > > > > uint64_t *value);
> > > > > |
> > > > > ~~^
> > > > >
> > > > > Signed-off-by: Richard W.M. Jones
> > > >
> > > > Why not simply make BDRVBlkioState.mem_region_alignment a uint64_t
> > > > instead of keeping it size_t and doing an additional conversion with
> > > > a check that requires an #if (probably to avoid a warning on 64 bit
> > > > hosts because the condition is never true)?
> > >
> > > The smaller change (attached) does work on i686, but this worries me a
> > > little (although it doesn't give any error or warning):
> > >
> > > if (((uintptr_t)host | size) % s->mem_region_alignment) {
> > > error_setg(errp, "unaligned buf %p with size %zu", host, size);
> > > return BMRR_FAIL;
> > > }
> >
> > I don't see the problem? The calculation will now be done in 64 bits
> > even on a 32 bit host, but that seems fine to me. Is there a trap I'm
> > missing?
>
> I guess not. Stefan, any comments on whether we need to worry about
> huge mem-region-alignment? I'll post the updated patch as a new
> message in a second.
An alignment of 32 or more bits is not required in any scenario that I'm
aware of.
Stefan
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Re: [PATCH [repost]] block/blkio: Don't assume size_t is 64 bit
On Tue, Jan 30, 2024 at 01:04:46PM +0100, Kevin Wolf wrote:
> Am 30.01.2024 um 11:30 hat Richard W.M. Jones geschrieben:
> > On Tue, Jan 30, 2024 at 09:51:59AM +0100, Kevin Wolf wrote:
> > > Am 29.01.2024 um 19:53 hat Richard W.M. Jones geschrieben:
> > > > With GCC 14 the code failed to compile on i686 (and was wrong for any
> > > > version of GCC):
> > > >
> > > > ../block/blkio.c: In function ‘blkio_file_open’:
> > > > ../block/blkio.c:857:28: error: passing argument 3 of
> > > > ‘blkio_get_uint64’ from incompatible pointer type
> > > > [-Wincompatible-pointer-types]
> > > > 857 |>mem_region_alignment);
> > > > |^~~~
> > > > ||
> > > > |size_t * {aka unsigned int *}
> > > > In file included from ../block/blkio.c:12:
> > > > /usr/include/blkio.h:49:67: note: expected ‘uint64_t *’ {aka ‘long long
> > > > unsigned int *’} but argument is of type ‘size_t *’ {aka ‘unsigned int
> > > > *’}
> > > >49 | int blkio_get_uint64(struct blkio *b, const char *name,
> > > > uint64_t *value);
> > > > |
> > > > ~~^
> > > >
> > > > Signed-off-by: Richard W.M. Jones
> > >
> > > Why not simply make BDRVBlkioState.mem_region_alignment a uint64_t
> > > instead of keeping it size_t and doing an additional conversion with
> > > a check that requires an #if (probably to avoid a warning on 64 bit
> > > hosts because the condition is never true)?
> >
> > The smaller change (attached) does work on i686, but this worries me a
> > little (although it doesn't give any error or warning):
> >
> > if (((uintptr_t)host | size) % s->mem_region_alignment) {
> > error_setg(errp, "unaligned buf %p with size %zu", host, size);
> > return BMRR_FAIL;
> > }
>
> I don't see the problem? The calculation will now be done in 64 bits
> even on a 32 bit host, but that seems fine to me. Is there a trap I'm
> missing?
I guess not. Stefan, any comments on whether we need to worry about
huge mem-region-alignment? I'll post the updated patch as a new
message in a second.
Rich.
> Kevin
>
> > From 500f3a81652dcefa79a4864c1f3fa6747c16952e Mon Sep 17 00:00:00 2001
> > From: "Richard W.M. Jones"
> > Date: Mon, 29 Jan 2024 18:20:46 +
> > Subject: [PATCH] block/blkio: Make s->mem_region_alignment be 64 bits
> > MIME-Version: 1.0
> > Content-Type: text/plain; charset=UTF-8
> > Content-Transfer-Encoding: 8bit
> >
> > With GCC 14 the code failed to compile on i686 (and was wrong for any
> > version of GCC):
> >
> > ../block/blkio.c: In function ‘blkio_file_open’:
> > ../block/blkio.c:857:28: error: passing argument 3 of ‘blkio_get_uint64’
> > from incompatible pointer type [-Wincompatible-pointer-types]
> > 857 |>mem_region_alignment);
> > |^~~~
> > ||
> > |size_t * {aka unsigned int *}
> > In file included from ../block/blkio.c:12:
> > /usr/include/blkio.h:49:67: note: expected ‘uint64_t *’ {aka ‘long long
> > unsigned int *’} but argument is of type ‘size_t *’ {aka ‘unsigned int *’}
> >49 | int blkio_get_uint64(struct blkio *b, const char *name, uint64_t
> > *value);
> > |
> > ~~^
> >
> > Signed-off-by: Richard W.M. Jones
> > ---
> > block/blkio.c | 2 +-
> > 1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/block/blkio.c b/block/blkio.c
> > index 0a0a6c0f5fd..bc2f21784c7 100644
> > --- a/block/blkio.c
> > +++ b/block/blkio.c
> > @@ -68,7 +68,7 @@ typedef struct {
> > CoQueue bounce_available;
> >
> > /* The value of the "mem-region-alignment" property */
> > -size_t mem_region_alignment;
> > +uint64_t mem_region_alignment;
> >
> > /* Can we skip adding/deleting blkio_mem_regions? */
> > bool needs_mem_regions;
> > --
> > 2.43.0
> >
--
Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones
Read my programming and virtualization blog: http://rwmj.wordpress.com
Fedora Windows cross-compiler. Compile Windows programs, test, and
build Windows installers. Over 100 libraries supported.
http://fedoraproject.org/wiki/MinGW
Re: [PATCH [repost]] block/blkio: Don't assume size_t is 64 bit
Am 30.01.2024 um 11:30 hat Richard W.M. Jones geschrieben:
> On Tue, Jan 30, 2024 at 09:51:59AM +0100, Kevin Wolf wrote:
> > Am 29.01.2024 um 19:53 hat Richard W.M. Jones geschrieben:
> > > With GCC 14 the code failed to compile on i686 (and was wrong for any
> > > version of GCC):
> > >
> > > ../block/blkio.c: In function ‘blkio_file_open’:
> > > ../block/blkio.c:857:28: error: passing argument 3 of ‘blkio_get_uint64’
> > > from incompatible pointer type [-Wincompatible-pointer-types]
> > > 857 |>mem_region_alignment);
> > > |^~~~
> > > ||
> > > |size_t * {aka unsigned int *}
> > > In file included from ../block/blkio.c:12:
> > > /usr/include/blkio.h:49:67: note: expected ‘uint64_t *’ {aka ‘long long
> > > unsigned int *’} but argument is of type ‘size_t *’ {aka ‘unsigned int *’}
> > >49 | int blkio_get_uint64(struct blkio *b, const char *name, uint64_t
> > > *value);
> > > |
> > > ~~^
> > >
> > > Signed-off-by: Richard W.M. Jones
> >
> > Why not simply make BDRVBlkioState.mem_region_alignment a uint64_t
> > instead of keeping it size_t and doing an additional conversion with
> > a check that requires an #if (probably to avoid a warning on 64 bit
> > hosts because the condition is never true)?
>
> The smaller change (attached) does work on i686, but this worries me a
> little (although it doesn't give any error or warning):
>
> if (((uintptr_t)host | size) % s->mem_region_alignment) {
> error_setg(errp, "unaligned buf %p with size %zu", host, size);
> return BMRR_FAIL;
> }
I don't see the problem? The calculation will now be done in 64 bits
even on a 32 bit host, but that seems fine to me. Is there a trap I'm
missing?
Kevin
> From 500f3a81652dcefa79a4864c1f3fa6747c16952e Mon Sep 17 00:00:00 2001
> From: "Richard W.M. Jones"
> Date: Mon, 29 Jan 2024 18:20:46 +
> Subject: [PATCH] block/blkio: Make s->mem_region_alignment be 64 bits
> MIME-Version: 1.0
> Content-Type: text/plain; charset=UTF-8
> Content-Transfer-Encoding: 8bit
>
> With GCC 14 the code failed to compile on i686 (and was wrong for any
> version of GCC):
>
> ../block/blkio.c: In function ‘blkio_file_open’:
> ../block/blkio.c:857:28: error: passing argument 3 of ‘blkio_get_uint64’ from
> incompatible pointer type [-Wincompatible-pointer-types]
> 857 |>mem_region_alignment);
> |^~~~
> ||
> |size_t * {aka unsigned int *}
> In file included from ../block/blkio.c:12:
> /usr/include/blkio.h:49:67: note: expected ‘uint64_t *’ {aka ‘long long
> unsigned int *’} but argument is of type ‘size_t *’ {aka ‘unsigned int *’}
>49 | int blkio_get_uint64(struct blkio *b, const char *name, uint64_t
> *value);
> |
> ~~^
>
> Signed-off-by: Richard W.M. Jones
> ---
> block/blkio.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/block/blkio.c b/block/blkio.c
> index 0a0a6c0f5fd..bc2f21784c7 100644
> --- a/block/blkio.c
> +++ b/block/blkio.c
> @@ -68,7 +68,7 @@ typedef struct {
> CoQueue bounce_available;
>
> /* The value of the "mem-region-alignment" property */
> -size_t mem_region_alignment;
> +uint64_t mem_region_alignment;
>
> /* Can we skip adding/deleting blkio_mem_regions? */
> bool needs_mem_regions;
> --
> 2.43.0
>
Re: [PATCH [repost]] block/blkio: Don't assume size_t is 64 bit
On Tue, Jan 30, 2024 at 09:51:59AM +0100, Kevin Wolf wrote:
> Am 29.01.2024 um 19:53 hat Richard W.M. Jones geschrieben:
> > With GCC 14 the code failed to compile on i686 (and was wrong for any
> > version of GCC):
> >
> > ../block/blkio.c: In function ‘blkio_file_open’:
> > ../block/blkio.c:857:28: error: passing argument 3 of ‘blkio_get_uint64’
> > from incompatible pointer type [-Wincompatible-pointer-types]
> > 857 |>mem_region_alignment);
> > |^~~~
> > ||
> > |size_t * {aka unsigned int *}
> > In file included from ../block/blkio.c:12:
> > /usr/include/blkio.h:49:67: note: expected ‘uint64_t *’ {aka ‘long long
> > unsigned int *’} but argument is of type ‘size_t *’ {aka ‘unsigned int *’}
> >49 | int blkio_get_uint64(struct blkio *b, const char *name, uint64_t
> > *value);
> > |
> > ~~^
> >
> > Signed-off-by: Richard W.M. Jones
>
> Why not simply make BDRVBlkioState.mem_region_alignment a uint64_t
> instead of keeping it size_t and doing an additional conversion with
> a check that requires an #if (probably to avoid a warning on 64 bit
> hosts because the condition is never true)?
The smaller change (attached) does work on i686, but this worries me a
little (although it doesn't give any error or warning):
if (((uintptr_t)host | size) % s->mem_region_alignment) {
error_setg(errp, "unaligned buf %p with size %zu", host, size);
return BMRR_FAIL;
}
Rich.
> Kevin
>
> > block/blkio.c | 12 +++-
> > 1 file changed, 11 insertions(+), 1 deletion(-)
> >
> > diff --git a/block/blkio.c b/block/blkio.c
> > index 0a0a6c0f5fd..52d78935147 100644
> > --- a/block/blkio.c
> > +++ b/block/blkio.c
> > @@ -794,6 +794,7 @@ static int blkio_file_open(BlockDriverState *bs, QDict
> > *options, int flags,
> > const char *blkio_driver = bs->drv->protocol_name;
> > BDRVBlkioState *s = bs->opaque;
> > int ret;
> > +uint64_t val;
> >
> > ret = blkio_create(blkio_driver, >blkio);
> > if (ret < 0) {
> > @@ -854,7 +855,7 @@ static int blkio_file_open(BlockDriverState *bs, QDict
> > *options, int flags,
> >
> > ret = blkio_get_uint64(s->blkio,
> > "mem-region-alignment",
> > - >mem_region_alignment);
> > + );
> > if (ret < 0) {
> > error_setg_errno(errp, -ret,
> > "failed to get mem-region-alignment: %s",
> > @@ -862,6 +863,15 @@ static int blkio_file_open(BlockDriverState *bs, QDict
> > *options, int flags,
> > blkio_destroy(>blkio);
> > return ret;
> > }
> > +#if HOST_LONG_BITS == 32
> > +if (val > SIZE_MAX) {
> > +error_setg_errno(errp, ERANGE,
> > + "mem-region-alignment too large for size_t");
> > +blkio_destroy(>blkio);
> > +return -ERANGE;
> > +}
> > +#endif
> > +s->mem_region_alignment = (size_t)val;
> >
> > ret = blkio_get_bool(s->blkio,
> > "may-pin-mem-regions",
> > --
> > 2.43.0
> >
--
Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones
Read my programming and virtualization blog: http://rwmj.wordpress.com
libguestfs lets you edit virtual machines. Supports shell scripting,
bindings from many languages. http://libguestfs.org
>From 500f3a81652dcefa79a4864c1f3fa6747c16952e Mon Sep 17 00:00:00 2001
From: "Richard W.M. Jones"
Date: Mon, 29 Jan 2024 18:20:46 +
Subject: [PATCH] block/blkio: Make s->mem_region_alignment be 64 bits
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
With GCC 14 the code failed to compile on i686 (and was wrong for any
version of GCC):
../block/blkio.c: In function ‘blkio_file_open’:
../block/blkio.c:857:28: error: passing argument 3 of ‘blkio_get_uint64’ from
incompatible pointer type [-Wincompatible-pointer-types]
857 |>mem_region_alignment);
|^~~~
||
|size_t * {aka unsigned int *}
In file included from ../block/blkio.c:12:
/usr/include/blkio.h:49:67: note: expected ‘uint64_t *’ {aka ‘long long
unsigned int *’} but argument is of type ‘size_t *’ {aka ‘unsigned int *’}
49 | int blkio_get_uint64(struct blkio *b, const char *name, uint64_t
*value);
| ~~^
Signed-off-by: Richard W.M. Jones
---
block/blkio.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/block/blkio.c b/block/blkio.c
index 0a0a6c0f5fd..bc2f21784c7 100644
--- a/block/blkio.c
+++ b/block/blkio.c
@@ -68,7 +68,7 @@ typedef struct {
CoQueue bounce_available;
/*
Re: [PATCH [repost]] block/blkio: Don't assume size_t is 64 bit
Am 29.01.2024 um 19:53 hat Richard W.M. Jones geschrieben:
> With GCC 14 the code failed to compile on i686 (and was wrong for any
> version of GCC):
>
> ../block/blkio.c: In function ‘blkio_file_open’:
> ../block/blkio.c:857:28: error: passing argument 3 of ‘blkio_get_uint64’ from
> incompatible pointer type [-Wincompatible-pointer-types]
> 857 |>mem_region_alignment);
> |^~~~
> ||
> |size_t * {aka unsigned int *}
> In file included from ../block/blkio.c:12:
> /usr/include/blkio.h:49:67: note: expected ‘uint64_t *’ {aka ‘long long
> unsigned int *’} but argument is of type ‘size_t *’ {aka ‘unsigned int *’}
>49 | int blkio_get_uint64(struct blkio *b, const char *name, uint64_t
> *value);
> |
> ~~^
>
> Signed-off-by: Richard W.M. Jones
Why not simply make BDRVBlkioState.mem_region_alignment a uint64_t
instead of keeping it size_t and doing an additional conversion with
a check that requires an #if (probably to avoid a warning on 64 bit
hosts because the condition is never true)?
Kevin
> block/blkio.c | 12 +++-
> 1 file changed, 11 insertions(+), 1 deletion(-)
>
> diff --git a/block/blkio.c b/block/blkio.c
> index 0a0a6c0f5fd..52d78935147 100644
> --- a/block/blkio.c
> +++ b/block/blkio.c
> @@ -794,6 +794,7 @@ static int blkio_file_open(BlockDriverState *bs, QDict
> *options, int flags,
> const char *blkio_driver = bs->drv->protocol_name;
> BDRVBlkioState *s = bs->opaque;
> int ret;
> +uint64_t val;
>
> ret = blkio_create(blkio_driver, >blkio);
> if (ret < 0) {
> @@ -854,7 +855,7 @@ static int blkio_file_open(BlockDriverState *bs, QDict
> *options, int flags,
>
> ret = blkio_get_uint64(s->blkio,
> "mem-region-alignment",
> - >mem_region_alignment);
> + );
> if (ret < 0) {
> error_setg_errno(errp, -ret,
> "failed to get mem-region-alignment: %s",
> @@ -862,6 +863,15 @@ static int blkio_file_open(BlockDriverState *bs, QDict
> *options, int flags,
> blkio_destroy(>blkio);
> return ret;
> }
> +#if HOST_LONG_BITS == 32
> +if (val > SIZE_MAX) {
> +error_setg_errno(errp, ERANGE,
> + "mem-region-alignment too large for size_t");
> +blkio_destroy(>blkio);
> +return -ERANGE;
> +}
> +#endif
> +s->mem_region_alignment = (size_t)val;
>
> ret = blkio_get_bool(s->blkio,
> "may-pin-mem-regions",
> --
> 2.43.0
>
Re: [PATCH [repost]] block/blkio: Don't assume size_t is 64 bit
On Mon, Jan 29, 2024 at 06:53:55PM +, Richard W.M. Jones wrote:
> With GCC 14 the code failed to compile on i686 (and was wrong for any
> version of GCC):
>
> ../block/blkio.c: In function ‘blkio_file_open’:
> ../block/blkio.c:857:28: error: passing argument 3 of ‘blkio_get_uint64’ from
> incompatible pointer type [-Wincompatible-pointer-types]
> 857 |>mem_region_alignment);
> |^~~~
> ||
> |size_t * {aka unsigned int *}
> In file included from ../block/blkio.c:12:
> /usr/include/blkio.h:49:67: note: expected ‘uint64_t *’ {aka ‘long long
> unsigned int *’} but argument is of type ‘size_t *’ {aka ‘unsigned int *’}
>49 | int blkio_get_uint64(struct blkio *b, const char *name, uint64_t
> *value);
> |
> ~~^
I wish gcc could point this out even when compiling on a 64-bit
platform where size_t and uint64_t happen to share the same type, by
reasoning about the underlying typedefs being different. But that's a
bigger task for gcc, and not one for this group.
>
> Signed-off-by: Richard W.M. Jones
> ---
> block/blkio.c | 12 +++-
> 1 file changed, 11 insertions(+), 1 deletion(-)
Reviewed-by: Eric Blake
--
Eric Blake, Principal Software Engineer
Red Hat, Inc.
Virtualization: qemu.org | libguestfs.org
[PATCH [repost]] block/blkio: Don't assume size_t is 64 bit
With GCC 14 the code failed to compile on i686 (and was wrong for any
version of GCC):
../block/blkio.c: In function ‘blkio_file_open’:
../block/blkio.c:857:28: error: passing argument 3 of ‘blkio_get_uint64’ from
incompatible pointer type [-Wincompatible-pointer-types]
857 |>mem_region_alignment);
|^~~~
||
|size_t * {aka unsigned int *}
In file included from ../block/blkio.c:12:
/usr/include/blkio.h:49:67: note: expected ‘uint64_t *’ {aka ‘long long
unsigned int *’} but argument is of type ‘size_t *’ {aka ‘unsigned int *’}
49 | int blkio_get_uint64(struct blkio *b, const char *name, uint64_t
*value);
| ~~^
Signed-off-by: Richard W.M. Jones
---
block/blkio.c | 12 +++-
1 file changed, 11 insertions(+), 1 deletion(-)
diff --git a/block/blkio.c b/block/blkio.c
index 0a0a6c0f5fd..52d78935147 100644
--- a/block/blkio.c
+++ b/block/blkio.c
@@ -794,6 +794,7 @@ static int blkio_file_open(BlockDriverState *bs, QDict
*options, int flags,
const char *blkio_driver = bs->drv->protocol_name;
BDRVBlkioState *s = bs->opaque;
int ret;
+uint64_t val;
ret = blkio_create(blkio_driver, >blkio);
if (ret < 0) {
@@ -854,7 +855,7 @@ static int blkio_file_open(BlockDriverState *bs, QDict
*options, int flags,
ret = blkio_get_uint64(s->blkio,
"mem-region-alignment",
- >mem_region_alignment);
+ );
if (ret < 0) {
error_setg_errno(errp, -ret,
"failed to get mem-region-alignment: %s",
@@ -862,6 +863,15 @@ static int blkio_file_open(BlockDriverState *bs, QDict
*options, int flags,
blkio_destroy(>blkio);
return ret;
}
+#if HOST_LONG_BITS == 32
+if (val > SIZE_MAX) {
+error_setg_errno(errp, ERANGE,
+ "mem-region-alignment too large for size_t");
+blkio_destroy(>blkio);
+return -ERANGE;
+}
+#endif
+s->mem_region_alignment = (size_t)val;
ret = blkio_get_bool(s->blkio,
"may-pin-mem-regions",
--
2.43.0
[PATCH [repost]] block/blkio: Don't assume size_t is 64 bit
Repost of the same patch as a minute ago because I messed up a couple of email addresses in the CC. Rich.
