| Message ID | 1311602584-23409-17-git-send-email-avi@redhat.com |
|---|---|
| State | New |
| Headers | show |
On 07/25/2011 09:02 AM, Avi Kivity wrote: > The I/O port space is byte addressable, even for word and long accesses. > > An example is the VMware svga card, which has long ports on offsets 0, > 1, and 2. > > Signed-off-by: Avi Kivity<avi@redhat.com> I've always thought this was odd but didn't know of a specific circumstance where it broke a device. This was a big problem with the old API. Devices don't register their interest in specific sizes. They may ignore certain size accesses but that's a device specific behavior. Reviewed-by: Anthony Liguori <aliguori@us.ibm.com> Regards, Anthony Liguori > --- > ioport.c | 4 ++-- > 1 files changed, 2 insertions(+), 2 deletions(-) > > diff --git a/ioport.c b/ioport.c > index 0d2611d..a32483b 100644 > --- a/ioport.c > +++ b/ioport.c > @@ -146,7 +146,7 @@ int register_ioport_read(pio_addr_t start, int length, int size, > hw_error("register_ioport_read: invalid size"); > return -1; > } > - for(i = start; i< start + length; i += size) { > + for(i = start; i< start + length; ++i) { > ioport_read_table[bsize][i] = func; > if (ioport_opaque[i] != NULL&& ioport_opaque[i] != opaque) > hw_error("register_ioport_read: invalid opaque for address 0x%x", > @@ -166,7 +166,7 @@ int register_ioport_write(pio_addr_t start, int length, int size, > hw_error("register_ioport_write: invalid size"); > return -1; > } > - for(i = start; i< start + length; i += size) { > + for(i = start; i< start + length; ++i) { > ioport_write_table[bsize][i] = func; > if (ioport_opaque[i] != NULL&& ioport_opaque[i] != opaque) > hw_error("register_ioport_write: invalid opaque for address 0x%x",
On 07/25/2011 10:20 PM, Anthony Liguori wrote: > On 07/25/2011 09:02 AM, Avi Kivity wrote: >> The I/O port space is byte addressable, even for word and long accesses. >> >> An example is the VMware svga card, which has long ports on offsets 0, >> 1, and 2. >> >> Signed-off-by: Avi Kivity<avi@redhat.com> > > I've always thought this was odd but didn't know of a specific > circumstance where it broke a device. > > This was a big problem with the old API. Devices don't register their > interest in specific sizes. They may ignore certain size accesses but > that's a device specific behavior. In fact there's on counterexample - 440FX consumes dword accesses on port cf8 but forwards byte and word accesses to the PCI bus. This cannot be implemented with the current API (it requires the opaque to be equal for all word sizes). The new API doesn't support it either; if we need to, we can re-issue the access but using the PCI address space instead of the root I/O address space. (of course this is purely theoretical)
diff --git a/ioport.c b/ioport.c index 0d2611d..a32483b 100644 --- a/ioport.c +++ b/ioport.c @@ -146,7 +146,7 @@ int register_ioport_read(pio_addr_t start, int length, int size, hw_error("register_ioport_read: invalid size"); return -1; } - for(i = start; i < start + length; i += size) { + for(i = start; i < start + length; ++i) { ioport_read_table[bsize][i] = func; if (ioport_opaque[i] != NULL && ioport_opaque[i] != opaque) hw_error("register_ioport_read: invalid opaque for address 0x%x", @@ -166,7 +166,7 @@ int register_ioport_write(pio_addr_t start, int length, int size, hw_error("register_ioport_write: invalid size"); return -1; } - for(i = start; i < start + length; i += size) { + for(i = start; i < start + length; ++i) { ioport_write_table[bsize][i] = func; if (ioport_opaque[i] != NULL && ioport_opaque[i] != opaque) hw_error("register_ioport_write: invalid opaque for address 0x%x",
The I/O port space is byte addressable, even for word and long accesses. An example is the VMware svga card, which has long ports on offsets 0, 1, and 2. Signed-off-by: Avi Kivity <avi@redhat.com> --- ioport.c | 4 ++-- 1 files changed, 2 insertions(+), 2 deletions(-)