On Thu, Jun 27, 2013 at 10:00:52AM -0700, Guenter Roeck wrote: > On Thu, Jun 27, 2013 at 10:45:01AM +0300, Michael S. Tsirkin wrote: > > On Wed, Jun 26, 2013 at 03:30:23PM -0700, Guenter Roeck wrote: > > > Enable support for MSI interrupts if the device supports it. > > > Since MSI interrupts are edge triggered, it is no longer necessary to > > > disable interrupts in the kernel and re-enable them from user-space. > > > Instead, clearing the interrupt condition in the user space application > > > automatically re-enables the interrupt. > > > > > > Signed-off-by: Guenter Roeck <linux@xxxxxxxxxxxx> > > > --- > > > An open question is if we can just do this unconditionally > > > or if there should be some flag to enable it. A module parameter, maybe ? > > > > NACK > > > > UIO is for devices that don't do memory writes. > > Anything that can do writes must be protected by an IOMMU > > and/or have a secure kernel driver, not a UIO stub. > > > > MSI is done by memory writes so if userspace > > controls the device it can trick it to write > > anywhere in memory. > > > Just out of curiosity: Since MSI support is mandatory for all PCIE devices, > isn't that possible anyway, even if MSI is not enabled by the kernel ? > All one would need to do is to enable MSI from user space; after all, > the chip configuration space is writable. > > Thanks, > Guenter If a device has capability to do writes, sure. So don't do this then :) -- MST -- To unsubscribe from this list: send the line "unsubscribe linux-doc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
