From: "Roedel, Joerg" <Joerg.Roedel@amd.com>
To: Avi Kivity <avi@redhat.com>
Cc: Marcelo Tosatti <mtosatti@redhat.com>,
Alexander Graf <agraf@suse.de>,
"joro@8bytes.org" <joro@8bytes.org>,
"kvm@vger.kernel.org" <kvm@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 10/27] KVM: MMU: Add infrastructure for two-level page walker
Date: Wed, 8 Sep 2010 11:20:14 +0200 [thread overview]
Message-ID: <20100908092013.GK2177@amd.com> (raw)
In-Reply-To: <4C852D6F.5000101@redhat.com>
On Mon, Sep 06, 2010 at 02:05:35PM -0400, Avi Kivity wrote:
> On 09/06/2010 06:55 PM, Joerg Roedel wrote:
> > This patch introduces a mmu-callback to translate gpa
> > addresses in the walk_addr code. This is later used to
> > translate l2_gpa addresses into l1_gpa addresses.
>
> > @@ -534,6 +534,11 @@ static inline gpa_t gfn_to_gpa(gfn_t gfn)
> > return (gpa_t)gfn<< PAGE_SHIFT;
> > }
> >
> > +static inline gfn_t gpa_to_gfn(gpa_t gpa)
> > +{
> > + return (gfn_t)gpa>> PAGE_SHIFT;
> > +}
> > +
>
> That's a bug - gfn_t may be smaller than gpa_t, so you're truncating
> just before the shift. Note the casts in the surrounding functions are
> widening, not narrowing.
>
> However, gfn_t is u64 so the bug is only theoretical.
Will fix that in v4 too. Thanks.
Joerg
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AMD Operating System Research Center
Advanced Micro Devices GmbH Einsteinring 24 85609 Dornach
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Registration: Dornach, Landkr. Muenchen; Registerger. Muenchen, HRB Nr. 43632
next prev parent reply other threads:[~2010-09-08 9:21 UTC|newest]
Thread overview: 40+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-09-06 15:55 [PATCH 0/27] Nested Paging Virtualization for KVM v3 (now with fixed Cc-List) Joerg Roedel
2010-09-06 15:55 ` [PATCH 01/27] KVM: MMU: Check for root_level instead of long mode Joerg Roedel
2010-09-06 15:55 ` [PATCH 02/27] KVM: MMU: Make tdp_enabled a mmu-context parameter Joerg Roedel
2010-09-06 15:55 ` [PATCH 03/27] KVM: MMU: Make set_cr3 a function pointer in kvm_mmu Joerg Roedel
2010-09-06 15:55 ` [PATCH 04/27] KVM: X86: Introduce a tdp_set_cr3 function Joerg Roedel
2010-09-06 15:55 ` [PATCH 05/27] KVM: MMU: Introduce get_cr3 function pointer Joerg Roedel
2010-09-06 15:55 ` [PATCH 06/27] KVM: MMU: Introduce inject_page_fault " Joerg Roedel
2010-09-06 15:55 ` [PATCH 07/27] KVM: MMU: Introduce kvm_init_shadow_mmu helper function Joerg Roedel
2010-09-06 15:55 ` [PATCH 08/27] KVM: MMU: Let is_rsvd_bits_set take mmu context instead of vcpu Joerg Roedel
2010-09-06 15:55 ` [PATCH 09/27] KVM: MMU: Introduce generic walk_addr function Joerg Roedel
2010-09-06 15:55 ` [PATCH 10/27] KVM: MMU: Add infrastructure for two-level page walker Joerg Roedel
2010-09-06 18:05 ` Avi Kivity
2010-09-08 9:20 ` Roedel, Joerg [this message]
2010-09-06 15:55 ` [PATCH 11/27] KVM: X86: Introduce pointer to mmu context used for gva_to_gpa Joerg Roedel
2010-09-06 15:55 ` [PATCH 12/27] KVM: MMU: Implement nested gva_to_gpa functions Joerg Roedel
2010-09-06 15:55 ` [PATCH 13/27] KVM: X86: Add kvm_read_guest_page_tdp function Joerg Roedel
2010-09-06 15:55 ` [PATCH 14/27] KVM: MMU: Make walk_addr_generic capable for two-level walking Joerg Roedel
2010-09-07 17:48 ` Marcelo Tosatti
2010-09-08 9:12 ` Roedel, Joerg
2010-09-06 15:55 ` [PATCH 15/27] KVM: MMU: Introduce kvm_read_guest_page_x86() Joerg Roedel
2010-09-06 15:55 ` [PATCH 16/27] KVM: MMU: Introduce init_kvm_nested_mmu() Joerg Roedel
2010-09-06 15:55 ` [PATCH 17/27] KVM: MMU: Track page fault data in struct vcpu Joerg Roedel
2010-09-06 18:17 ` Avi Kivity
2010-09-06 15:55 ` [PATCH 18/27] KVM: MMU: Propagate the right fault back to the guest after gva_to_gpa Joerg Roedel
2010-09-06 15:55 ` [PATCH 19/27] KVM: X86: Propagate fetch faults Joerg Roedel
2010-09-07 18:43 ` Marcelo Tosatti
2010-09-08 9:18 ` Roedel, Joerg
2010-09-06 15:55 ` [PATCH 20/27] KVM: MMU: Add kvm_mmu parameter to load_pdptrs function Joerg Roedel
2010-09-06 15:56 ` [PATCH 21/27] KVM: MMU: Introduce kvm_pdptr_read_mmu Joerg Roedel
2010-09-06 15:56 ` [PATCH 22/27] KVM: MMU: Refactor mmu_alloc_roots function Joerg Roedel
2010-09-07 20:39 ` Marcelo Tosatti
2010-09-08 7:16 ` Avi Kivity
2010-09-08 9:16 ` Roedel, Joerg
2010-09-06 15:56 ` [PATCH 23/27] KVM: MMU: Allow long mode shadows for legacy page tables Joerg Roedel
2010-09-06 15:56 ` [PATCH 24/27] KVM: SVM: Implement MMU helper functions for Nested Nested Paging Joerg Roedel
2010-09-06 15:56 ` [PATCH 25/27] KVM: SVM: Initialize Nested Nested MMU context on VMRUN Joerg Roedel
2010-09-06 15:56 ` [PATCH 26/27] KVM: SVM: Expect two more candiates for exit_int_info Joerg Roedel
2010-09-06 15:56 ` [PATCH 27/27] KVM: SVM: Report Nested Paging support to userspace Joerg Roedel
2010-09-06 18:37 ` [PATCH 0/27] Nested Paging Virtualization for KVM v3 (now with fixed Cc-List) Avi Kivity
2010-09-07 16:35 ` Roedel, Joerg
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