On Wed, May 04, 2016 at 04:04:24PM +0200, Alexander Gordeev wrote:
> On Wed, May 04, 2016 at 02:24:04PM +0200, Andrew Jones wrote:
> > On Wed, May 04, 2016 at 12:31:36PM +0200, Alexander Gordeev wrote:
> > > Cc: Andrew Jones <drjones@xxxxxxxxxx>
> > > Cc: Thomas Huth <thuth@xxxxxxxxxx>
> > > Cc: Radim Krčmář <rkrcmar@xxxxxxxxxx>
> > > Reviewed-by: Andrew Jones <drjones@xxxxxxxxxx>
> > > Signed-off-by: Alexander Gordeev <agordeev@xxxxxxxxxx>
> > > ---
> > > lib/x86/asm/io.h | 2 ++
> > > lib/x86/io.c | 15 +++++++++++++++
> > > x86/vmexit.c | 10 ++--------
> > > 3 files changed, 19 insertions(+), 8 deletions(-)
> > >
> > > diff --git a/lib/x86/asm/io.h b/lib/x86/asm/io.h
> > > index 83387b5..2436822 100644
> > > --- a/lib/x86/asm/io.h
> > > +++ b/lib/x86/asm/io.h
> > > @@ -49,4 +49,6 @@ static inline void *phys_to_virt(unsigned long phys)
> > > return (void *)phys;
> > > }
> > >
> > > +void __iomem *ioremap(phys_addr_t phys_addr, size_t size);
> > > +
> > > #endif
> > > diff --git a/lib/x86/io.c b/lib/x86/io.c
> > > index d396d42..c49926a 100644
> > > --- a/lib/x86/io.c
> > > +++ b/lib/x86/io.c
> > > @@ -1,6 +1,8 @@
> > > #include "libcflat.h"
> > > +#include "vm.h"
> > > #include "smp.h"
> > > #include "asm/io.h"
> > > +#include "asm/page.h"
> > > #ifndef USE_SERIAL
> > > #define USE_SERIAL
> > > #endif
> > > @@ -81,3 +83,16 @@ void exit(int code)
> > > asm volatile("out %0, %1" : : "a"(code), "d"((short)0xf4));
> > > #endif
> > > }
> > > +
> > > +void __iomem *ioremap(phys_addr_t phys_addr, size_t size)
> > > +{
> > > + phys_addr_t base = phys_addr & PAGE_MASK;
> > > + phys_addr_t offset = phys_addr - base;
> > > +
> > > + /*
> > > + * The kernel sets PTEs for an ioremap() with page cache disabled.
> > > + * It would make sense that I/O mappings would be uncached -
> > > + * and may help us find bugs when we properly map that way.
> >
> > You left out the 'but' ("...that way, but we don't currently. Maybe we
> > should add a vmap_uncached?"), or something like that.
>
> If this one is better?
Not really :-) I'd stick with what you have above, but extending it
with some sort of 'but we don't do that right now'.
>
> "
> Andrew Jones noted: "The kernel sets the PTEs for an ioremap with PCD,
> page cache disabled. I guess we can live without that, but it would
> make sense that I/O mappings would be uncached - and may help us find
> bugs when we properly map that way."
> "
>
> As of vmap_uncached - I guess since vmap() has a broader "scope" than
> just IO it would make sense to introduce vmap_prot() instead. Or
> add an extra page protection parameter to the existing vmap(). I could
> do that with a follow-up patch.
You don't really need to write vmap_uncached unless you plan to move
unit tests to it too. We'd need sign-off from the unit test developers
for that though. BTW, I'd still add a vmap_uncached, but it can
certainly wrap a vmap_prot. I wouldn't extend vmap though. The default
flags will almost always be correct, so having to pass them in (or a
zero to be ORed with them) all the time wouldn't be nice.
drew
>
> > > + */
> > > + return vmap(phys_addr, size) + offset;
> > > +}
> > > diff --git a/x86/vmexit.c b/x86/vmexit.c
> > > index db7dbd8..c2e1e49 100644
> > > --- a/x86/vmexit.c
> > > +++ b/x86/vmexit.c
> > > @@ -371,8 +371,7 @@ int main(int ac, char **av)
> > > {
> > > struct fadt_descriptor_rev1 *fadt;
> > > int i;
> > > - unsigned long membar = 0, base, offset;
> > > - void *m;
> > > + unsigned long membar = 0;
> > > pcidevaddr_t pcidev;
> > >
> > > smp_init();
> > > @@ -394,12 +393,7 @@ int main(int ac, char **av)
> > > }
> > > if (pci_bar_is_memory(pcidev, i)) {
> > > membar = pci_bar_addr(pcidev, i);
> > > - base = membar & ~4095;
> > > - offset = membar - base;
> > > - m = alloc_vpages(1);
> > > -
> > > - install_page((void *)read_cr3(), base, m);
> > > - pci_test.memaddr = m + offset;
> > > + pci_test.memaddr = ioremap(membar, PAGE_SIZE);
> > > } else {
> > > pci_test.iobar = pci_bar_addr(pcidev, i);
> > > }
> > > --
> > > 1.8.3.1
> > >
> > > --
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