Messages in this thread | | | Date | Tue, 27 Apr 2010 16:37:42 +0300 | From | Avi Kivity <> | Subject | Re: [PATCH 16/22] KVM: MMU: Track page fault data in struct vcpu |
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On 04/27/2010 04:28 PM, Joerg Roedel wrote: > >>> diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h >>> index d9dfc8c..8426870 100644 >>> --- a/arch/x86/include/asm/kvm_host.h >>> +++ b/arch/x86/include/asm/kvm_host.h >>> @@ -298,6 +298,9 @@ struct kvm_vcpu_arch { >>> /* Used for two dimensional paging emulation */ >>> struct kvm_mmu nested_mmu; >>> >>> + unsigned long fault_address; >>> >> Probably a problem on i386. How does npt handle faults when the >> guest is using pae paging and the host (in our case the guest...) >> isn't? I see it uses exit_info_2 for the address, which is a u64. >> > This shouldn't be an issue. If we run on 32bit host with nested paging > the guest can't have more than 4gb of addressable memory because of the > page table limitations (nested page table is always in host format). >
But the nested guest can use pae paging and generate a #NPF with exit_info_2 > 4GB. So we need to keep the full fault address; if we truncate, the guest might actually resolve the fault and let the nested guest continue.
-- error compiling committee.c: too many arguments to function
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