Bug#599089: linux-image-2.6.32-5-xen-686: Kernel Panics when using NFS from DomU to Dom0

[Jason Kendall <jakendall@gmail.com>]

Thats great Ian;

I'll test the patch later today or tomorrow and get you a confirmation.

Regards,
Jason


On 10-10-05 05:52 AM, Ian Campbell wrote:
> On Tue, 2010-10-05 at 10:47 +0100, Ian Campbell wrote:
>    
>> In addition to the kernel logging of the error I get this from the
>> hypervisor:
>> (XEN) mm.c:2062:d0 Error pfn 16d99: rd=ffff83011fefa000,
>> od=0000000000000000, caf=180000000000000, taf=0000000000000000
>> (XEN) mm.c:658:d0 Could not get page ref for pfn 16d99
>> (XEN) mm.c:3621:d0 Could not get page for mach->phys update
>>      
> Adding a bit more logging to the kernel I get:
> gnttb_copy_grant_page old c22ebcd8 P:0x1ec8e M:0xc499d F:0x41000000
> gnttb_copy_grant_page new c2324ce0 P:0x1fe18 M:0x11cd32 F:0x40000000
> (XEN) mm.c:2062:d0 Error pfn 1cd32: rd=ffff83011fefa000, od=0000000000000000, caf=180000000000000, taf=0000000000000000
> (XEN) mm.c:658:d0 Could not get page ref for pfn 1cd32
> (XEN) mm.c:3621:d0 Could not get page for mach->phys update
>
> Notice how MFN 0x11cd32 has become 0x1cd32 by the time it gets to the
> hypervisor!
>
> The following fixes it for me.
>
> From: Ian Campbell<ian.campbell@citrix.com>
> Subject: xen: grant table: do not truncate machine address on gnttab_copy_grant_page
>
> Signed-off-by: Ian Campbell<ian.campbell@citrix.com>
>
> --- a/drivers/xen/grant-table.c
> +++ b/drivers/xen/grant-table.c
> @@ -578,7 +578,7 @@ int gnttab_copy_grant_page(grant_ref_t ref, struct page **pagep)
>   	if (!xen_feature(XENFEAT_auto_translated_physmap)) {
>   		set_phys_to_machine(page_to_pfn(new_page), INVALID_P2M_ENTRY);
>
> -		mmu.ptr = (new_mfn<<  PAGE_SHIFT) | MMU_MACHPHYS_UPDATE;
> +		mmu.ptr = ((u64)new_mfn<<  PAGE_SHIFT) | MMU_MACHPHYS_UPDATE;
>   		mmu.val = pfn;
>   		err = HYPERVISOR_mmu_update(&mmu, 1, NULL, DOMID_SELF);
>   		BUG_ON(err);
>
>