[Xen-devel] Re: [PATCH 2 of 5] amd iommu: Fix iommu page size encoding when page order > 0

[Wei Wang2 <wei.wang2@xxxxxxx>]

On Thursday 03 November 2011 13:49:39 Jan Beulich wrote:
> >>> On 03.11.11 at 11:13, Wei Wang <wei.wang2@xxxxxxx> wrote:
> >
> > # HG changeset patch
> > # User Wei Wang <wei.wang2@xxxxxxx>
> > # Date 1320314617 -3600
> > # Node ID d0c38cb215cd96e01de27eadf5ec0a5e711de448
> > # Parent  d422e3cf7976c76c57fc2d455b784d0fcc24d06b
> > amd iommu: Fix iommu page size encoding when page order > 0
> >
> > Signed-off-by: Wei Wang <wei.wang2@xxxxxxx>
> >
> > diff -r d422e3cf7976 -r d0c38cb215cd
> > xen/drivers/passthrough/amd/iommu_map.c ---
> > a/xen/drivers/passthrough/amd/iommu_map.c   Thu Nov 03 11:02:17 2011 +0100
> > +++ b/xen/drivers/passthrough/amd/iommu_map.c       Thu Nov 03 11:03:37 2011
> > +0100 @@ -77,23 +77,24 @@ static void invalidate_iommu_pages(struc
> >  {
> >      u64 addr_lo, addr_hi;
> >      u32 cmd[4], entry;
> > -    u64 mask = 0;
> >      int sflag = 0, pde = 0;
> >
> > +    ASSERT ( order == 0 || order == 9 || order == 18 );
> > +
> > +    /* All pages associated with the domainID are invalidated */
> > +    if ( order || (io_addr == INV_IOMMU_ALL_PAGES_ADDRESS ) )
> > +    {
> > +        sflag = 1;
> > +        pde = 1;
> > +    }
> > +
> >      /* If sflag == 1, the size of the invalidate command is determined
> >       by the first zero bit in the address starting from Address[12] */
> > -    if ( order == 9 || order == 18 )
> > +    if ( order )
> >      {
> > -        mask = ((1ULL << (order - 1)) - 1) << PAGE_SHIFT;
> > -        io_addr |= mask;
> > -        sflag = 1;
> > -    }
> > -
> > -    /* All pages associated with the domainID are invalidated */
> > -    else if ( io_addr == 0x7FFFFFFFFFFFF000ULL )
>
> Note the difference between this and your adjusted definition
> of INV_IOMMU_ALL_PAGES_ADDRESS. I don't think this is
> correct (or else your patch description should say why).
>
> > -    {
> > -        sflag = 1;
> > -        pde = 1;
> > +        u64 mask = 1ULL << (order - 1 + PAGE_SHIFT);
> > +        io_addr &= ~mask;
> > +        io_addr |= mask - 1;
> >      }
> >
> >      addr_lo = io_addr & DMA_32BIT_MASK;
> > @@ -917,7 +918,7 @@ static void _amd_iommu_flush_pages(struc
> >
> >  void amd_iommu_flush_all_pages(struct domain *d)
> >  {
> > -    _amd_iommu_flush_pages(d, 0x7FFFFFFFFFFFFULL, 0);
> > +    _amd_iommu_flush_pages(d, INV_IOMMU_ALL_PAGES_ADDRESS, 0);
>
> Same here, for a slightly different reason.

The old code is wrong, here should be 0x7FFFFFFFFFFFF000ULL (or 
0x7FFFFFFFFFFFFULL << PAGE_SHIFT)
iommu does not care about the last 12 bits. So in this patch  I just use
INV_IOMMU_ALL_PAGES_ADDRESS = 0x7FFFFFFFFFFFFFFFULL 

Wei 

> Jan
>
> >  }
> >
> >  void amd_iommu_flush_pages(struct domain *d,
> > diff -r d422e3cf7976 -r d0c38cb215cd
> > xen/include/asm-x86/hvm/svm/amd-iommu-defs.h ---
> > a/xen/include/asm-x86/hvm/svm/amd-iommu-defs.h      Thu Nov 03 11:02:17 2011
> > +0100 +++ b/xen/include/asm-x86/hvm/svm/amd-iommu-defs.h    Thu Nov 03
> > 11:03:37 2011 +0100
> > @@ -407,4 +407,6 @@
> >  #define INT_REMAP_ENTRY_VECTOR_MASK     0x00FF0000
> >  #define INT_REMAP_ENTRY_VECTOR_SHIFT    16
> >
> > +#define INV_IOMMU_ALL_PAGES_ADDRESS      0x7FFFFFFFFFFFFFFFULL
> > +
> >  #endif /* _ASM_X86_64_AMD_IOMMU_DEFS_H */




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