Re: [PATCH 16/22] KVM: MMU: Track page fault data in struct vcpu | KernelTrap

Re: [PATCH 16/22] KVM: MMU: Track page fault data in struct vcpu

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From: Roedel, Joerg

Subject: Re: [PATCH 16/22] KVM: MMU: Track page fault data in struct vcpu

Date: Tuesday, May 4, 2010 - 5:00 am

On Tue, May 04, 2010 at 05:50:50AM -0400, Avi Kivity wrote:
quoted text> On 05/04/2010 12:45 PM, Avi Kivity wrote:
> >
> >
> > Just a silly bug.  kvm_pdptr_read() can cause a guest memory read on 
> > svm, in this case with the mmu lock taken.  I'll post something to fix 
> > it.
> 
> I guess this was not reported because most svm machines have npt, and 
> this requires npt=0 to trigger.  Nonpae paging disables npt, so you were 
> hit.  Interestingly, nsvm makes it more likely to appear, since npt on 
> i386+pae will need the pdptrs.

Hmm, actually it happened on 32 bit with npt enabled. I think this
can trigger when mmu_alloc_roots is called for an pae guest because it
accidentially tries read the root_gfn from the guest before it figures
out that it runs with tdp and omits the gfn read from the guest.
I need to touch this for nested-npt and will look into a way improving
this.

	Joerg

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Messages in current thread:

[PATCH 0/22] Nested Paging support for Nested SVM v2, Joerg Roedel, (Tue Apr 27, 3:38 am)

[PATCH 01/22] KVM: MMU: Check for root_level instead of lo ..., Joerg Roedel, (Tue Apr 27, 3:38 am)

[PATCH 03/22] KVM: MMU: Make set_cr3 a function pointer in ..., Joerg Roedel, (Tue Apr 27, 3:38 am)

[PATCH 07/22] KVM: SVM: Implement MMU helper functions for ..., Joerg Roedel, (Tue Apr 27, 3:38 am)

[PATCH 09/22] KVM: MMU: Let is_rsvd_bits_set take mmu cont ..., Joerg Roedel, (Tue Apr 27, 3:38 am)

[PATCH 11/22] KVM: MMU: Add infrastructure for two-level p ..., Joerg Roedel, (Tue Apr 27, 3:38 am)

[PATCH 13/22] KVM: X86: Add kvm_read_guest_page_tdp function, Joerg Roedel, (Tue Apr 27, 3:38 am)

[PATCH 14/22] KVM: MMU: Make walk_addr_generic capable for ..., Joerg Roedel, (Tue Apr 27, 3:38 am)

[PATCH 16/22] KVM: MMU: Track page fault data in struct vcpu, Joerg Roedel, (Tue Apr 27, 3:38 am)

[PATCH 19/22] KVM: MMU: Introduce init_kvm_nested_mmu(), Joerg Roedel, (Tue Apr 27, 3:38 am)

[PATCH 20/22] KVM: SVM: Initialize Nested Nested MMU conte ..., Joerg Roedel, (Tue Apr 27, 3:38 am)

[PATCH 21/22] KVM: SVM: Report Nested Paging support to us ..., Joerg Roedel, (Tue Apr 27, 3:38 am)

Re: [PATCH 02/22] KVM: MMU: Make tdp_enabled a mmu-context ..., Avi Kivity, (Tue Apr 27, 5:06 am)

Re: [PATCH 11/22] KVM: MMU: Add infrastructure for two-lev ..., Avi Kivity, (Tue Apr 27, 5:34 am)

Re: [PATCH 12/22] KVM: MMU: Implement nested gva_to_gpa fu ..., Avi Kivity, (Tue Apr 27, 5:37 am)

Re: [PATCH 13/22] KVM: X86: Add kvm_read_guest_page_tdp fu ..., Avi Kivity, (Tue Apr 27, 5:42 am)

Re: [PATCH 16/22] KVM: MMU: Track page fault data in struc ..., Avi Kivity, (Tue Apr 27, 5:58 am)

Re: [PATCH 20/22] KVM: SVM: Initialize Nested Nested MMU c ..., Avi Kivity, (Tue Apr 27, 6:01 am)

Re: [PATCH 0/22] Nested Paging support for Nested SVM v2, Avi Kivity, (Tue Apr 27, 6:03 am)

Re: [PATCH 13/22] KVM: X86: Add kvm_read_guest_page_tdp fu ..., Joerg Roedel, (Tue Apr 27, 6:10 am)

Re: [PATCH 16/22] KVM: MMU: Track page fault data in struc ..., Joerg Roedel, (Tue Apr 27, 6:28 am)

Re: [PATCH 16/22] KVM: MMU: Track page fault data in struc ..., Avi Kivity, (Tue Apr 27, 6:37 am)

Re: [PATCH 16/22] KVM: MMU: Track page fault data in struc ..., Joerg Roedel, (Tue Apr 27, 6:57 am)

Re: [PATCH 16/22] KVM: MMU: Track page fault data in struc ..., Avi Kivity, (Tue Apr 27, 9:02 am)

Re: [PATCH 11/22] KVM: MMU: Add infrastructure for two-lev ..., Joerg Roedel, (Wed Apr 28, 3:52 am)

Re: [PATCH 11/22] KVM: MMU: Add infrastructure for two-lev ..., Joerg Roedel, (Wed Apr 28, 4:03 am)

Re: [PATCH 11/22] KVM: MMU: Add infrastructure for two-lev ..., Avi Kivity, (Wed Apr 28, 4:09 am)

Re: [PATCH 11/22] KVM: MMU: Add infrastructure for two-lev ..., Avi Kivity, (Wed Apr 28, 4:24 am)

Re: [PATCH 12/22] KVM: MMU: Implement nested gva_to_gpa fu ..., Joerg Roedel, (Wed Apr 28, 7:20 am)

Re: [PATCH 16/22] KVM: MMU: Track page fault data in struc ..., Joerg Roedel, (Mon May 3, 9:32 am)

Re: [PATCH 16/22] KVM: MMU: Track page fault data in struc ..., Avi Kivity, (Tue May 4, 12:53 am)

Re: [PATCH 16/22] KVM: MMU: Track page fault data in struc ..., Roedel, Joerg, (Tue May 4, 2:11 am)

Re: [PATCH 16/22] KVM: MMU: Track page fault data in struc ..., Avi Kivity, (Tue May 4, 2:20 am)

Re: [PATCH 16/22] KVM: MMU: Track page fault data in struc ..., Roedel, Joerg, (Tue May 4, 2:37 am)

Re: [PATCH 16/22] KVM: MMU: Track page fault data in struc ..., Avi Kivity, (Tue May 4, 2:45 am)

Re: [PATCH 16/22] KVM: M