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?
"
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.
> > + */
> > + 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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