But did you really see the NX bit? I think that (NX bit) would be a good
catch and it explains several failures of device drivers. We should fix
the creator of the pte (by __supported_pte_mask), not the consumer of
it.
We also need to fix Xen because Xen should not reject the request just
because it has the NX bit on.
Jun
---
Intel Open Source Technology Center
-----Original Message-----
From: xen-devel-bounces@xxxxxxxxxxxxxxxxxxx
[mailto:xen-devel-bounces@xxxxxxxxxxxxxxxxxxx] On Behalf Of Scott Parish
Sent: Tuesday, June 07, 2005 9:00 AM
To: xen-devel@xxxxxxxxxxxxxxxxxxx
Subject: Re: [Xen-devel] [patch] (resend) mask out nx bits when
calculatingpfn/mfn
Please ignore the first patch, it had a messed up macro.
sRp
On Tue, Jun 07, 2005 at 03:52:50PM +0000, Scott Parish wrote:
> This patch fixes a problem where it was possible (and seen) for the
> NX bit to not be masked out when calculating a pfn or mfn.
>
>
> sRp
>
> --
> Scott Parish
> Signed-off-by: srparish@xxxxxxxxxx
> diff -rN -u -p
old-xen-64-4/linux-2.6.11-xen-sparse/arch/xen/x86_64/kernel/pci-dma.c
new-xen-64-4/linux-2.6.11-xen-sparse/arch/xen/x86_64/kernel/pci-dma.c
> ---
old-xen-64-4/linux-2.6.11-xen-sparse/arch/xen/x86_64/kernel/pci-dma.c
2005-05-24 17:34:54.000000000 +0000
> +++
new-xen-64-4/linux-2.6.11-xen-sparse/arch/xen/x86_64/kernel/pci-dma.c
2005-06-07 15:35:43.000000000 +0000
> @@ -78,7 +78,7 @@ xen_contig_memory(unsigned long vstart,
> pud_t *pud;
> pmd_t *pmd;
> pte_t *pte;
> - unsigned long pfn, i, flags;
> + unsigned long mfn, i, flags;
>
> scrub_pages(vstart, 1 << order);
>
> @@ -90,16 +90,16 @@ xen_contig_memory(unsigned long vstart,
> pud = pud_offset(pgd, (vstart + (i*PAGE_SIZE)));
> pmd = pmd_offset(pud, (vstart + (i*PAGE_SIZE)));
> pte = pte_offset_kernel(pmd, (vstart + (i*PAGE_SIZE)));
> - pfn = pte->pte >> PAGE_SHIFT;
> + mfn = pte_mfn(*pte);
> xen_l1_entry_update(pte, 0);
> phys_to_machine_mapping[(__pa(vstart)>>PAGE_SHIFT)+i] =
> (u32)INVALID_P2M_ENTRY;
> if (HYPERVISOR_dom_mem_op(MEMOP_decrease_reservation,
> - &pfn, 1, 0) != 1) BUG();
> + &mfn, 1, 0) != 1) BUG();
> }
> /* 2. Get a new contiguous memory extent. */
> if (HYPERVISOR_dom_mem_op(MEMOP_increase_reservation,
> - &pfn, 1, order) != 1) BUG();
> + &mfn, 1, order) != 1) BUG();
> /* 3. Map the new extent in place of old pages. */
> for (i = 0; i < (1<<order); i++) {
> pgd = pgd_offset_k( (vstart + (i*PAGE_SIZE)));
> @@ -107,12 +107,12 @@ xen_contig_memory(unsigned long vstart,
> pmd = pmd_offset(pud, (vstart + (i*PAGE_SIZE)));
> pte = pte_offset_kernel(pmd, (vstart + (i*PAGE_SIZE)));
> xen_l1_entry_update(
> - pte, ((pfn+i)<<PAGE_SHIFT)|__PAGE_KERNEL);
> + pte, ((mfn+i)<<PAGE_SHIFT)|__PAGE_KERNEL);
> xen_machphys_update(
> - pfn+i, (__pa(vstart)>>PAGE_SHIFT)+i);
> + mfn+i, (__pa(vstart)>>PAGE_SHIFT)+i);
> phys_to_machine_mapping[(__pa(vstart)>>PAGE_SHIFT)+i] =
> - pfn+i;
> + mfn+i;
> }
> /* Flush updates through and flush the TLB. */
> xen_tlb_flush();
> diff -rN -u -p
old-xen-64-4/linux-2.6.11-xen-sparse/arch/xen/x86_64/mm/hypervisor.c
new-xen-64-4/linux-2.6.11-xen-sparse/arch/xen/x86_64/mm/hypervisor.c
> ---
old-xen-64-4/linux-2.6.11-xen-sparse/arch/xen/x86_64/mm/hypervisor.c
2005-06-06 16:39:54.000000000 +0000
> +++
new-xen-64-4/linux-2.6.11-xen-sparse/arch/xen/x86_64/mm/hypervisor.c
2005-06-07 15:39:31.000000000 +0000
> @@ -256,7 +256,7 @@ unsigned long allocate_empty_lowmem_regi
> pud = pud_offset(pgd, (vstart + (i*PAGE_SIZE)));
> pmd = pmd_offset(pud, (vstart + (i*PAGE_SIZE)));
> pte = pte_offset_kernel(pmd, (vstart + (i*PAGE_SIZE)));
> - pfn_array[i] = pte->pte >> PAGE_SHIFT;
> + pfn_array[i] = pte_mfn(*pte);
> xen_l1_entry_update(pte, 0);
> phys_to_machine_mapping[(__pa(vstart)>>PAGE_SHIFT)+i] =
> (u32)INVALID_P2M_ENTRY;
> diff -rN -u -p
old-xen-64-4/linux-2.6.11-xen-sparse/arch/xen/x86_64/mm/init.c
new-xen-64-4/linux-2.6.11-xen-sparse/arch/xen/x86_64/mm/init.c
> --- old-xen-64-4/linux-2.6.11-xen-sparse/arch/xen/x86_64/mm/init.c
2005-06-02 23:09:31.000000000 +0000
> +++ new-xen-64-4/linux-2.6.11-xen-sparse/arch/xen/x86_64/mm/init.c
2005-06-07 15:39:50.000000000 +0000
> @@ -395,7 +395,7 @@ unsigned long get_machine_pfn(unsigned l
> pmd_t* pmd = pmd_offset(pud, addr);
> pte_t *pte = pte_offset_kernel(pmd, addr);
>
> - return (pte->pte >> PAGE_SHIFT);
> + return pte_mfn(*pte);
> }
>
> #define ALIGN_TO_4K __attribute__((section(".data.page_aligned")))
> diff -rN -u -p
old-xen-64-4/linux-2.6.11-xen-sparse/include/asm-xen/asm-x86_64/pgtable.
h
new-xen-64-4/linux-2.6.11-xen-sparse/include/asm-xen/asm-x86_64/pgtable.
h
> ---
old-xen-64-4/linux-2.6.11-xen-sparse/include/asm-xen/asm-x86_64/pgtable.
h 2005-05-28 09:20:36.000000000 +0000
> +++
new-xen-64-4/linux-2.6.11-xen-sparse/include/asm-xen/asm-x86_64/pgtable.
h 2005-06-07 15:32:47.000000000 +0000
> @@ -277,9 +277,10 @@ static inline unsigned long pud_bad(pud_
> */
> #define INVALID_P2M_ENTRY (~0UL)
> #define FOREIGN_FRAME(_m) ((_m) | (1UL<<((sizeof(unsigned
long)*8)-1)))
> +#define pte_mfn(_pte) ((_pte).pte & PTE_MASK) >> PAGE_SHIFT;
> #define pte_pfn(_pte)
\
> ({
\
> - unsigned long mfn = (_pte).pte >> PAGE_SHIFT;
\
> + unsigned long mfn = pte_mfn(_pte);
\
> unsigned pfn = mfn_to_pfn(mfn);
\
> if ((pfn >= max_mapnr) || (pfn_to_mfn(pfn) != mfn))
\
> pfn = max_mapnr; /* special: force !pfn_valid() */
\
> _______________________________________________
> Xen-devel mailing list
> Xen-devel@xxxxxxxxxxxxxxxxxxx
> http://lists.xensource.com/xen-devel
--
Scott Parish
Signed-off-by: srparish@xxxxxxxxxx
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