On 04/20/2011 12:35 PM, Roedel, Joerg wrote:
On Wed, Apr 20, 2011 at 05:07:12AM -0400, Avi Kivity wrote: > On 04/18/2011 09:34 PM, Takuya Yoshikawa wrote: > > From: Takuya Yoshikawa<yoshikawa.tak...@oss.ntt.co.jp> > > > > This will be optimized later. > > > > Signed-off-by: Takuya Yoshikawa<yoshikawa.tak...@oss.ntt.co.jp> > > --- > > arch/x86/kvm/paging_tmpl.h | 12 +++++++++--- > > 1 files changed, 9 insertions(+), 3 deletions(-) > > > > diff --git a/arch/x86/kvm/paging_tmpl.h b/arch/x86/kvm/paging_tmpl.h > > index 74f8567..109939a 100644 > > --- a/arch/x86/kvm/paging_tmpl.h > > +++ b/arch/x86/kvm/paging_tmpl.h > > @@ -109,6 +109,14 @@ static unsigned FNAME(gpte_access)(struct kvm_vcpu *vcpu, pt_element_t gpte) > > return access; > > } > > > > +static int FNAME(read_guest_pte)(struct kvm_vcpu *vcpu, struct kvm_mmu *mmu, > > + gfn_t table_gfn, int offset, pt_element_t *ptep) > > +{ > > + return kvm_read_guest_page_mmu(vcpu, mmu, table_gfn, ptep, > > + offset, sizeof(*ptep), > > + PFERR_USER_MASK | PFERR_WRITE_MASK); > > +} > > + > > /* > > * Fetch a guest pte for a guest virtual address > > */ > > @@ -160,9 +168,7 @@ walk: > > walker->table_gfn[walker->level - 1] = table_gfn; > > walker->pte_gpa[walker->level - 1] = pte_gpa; > > > > - if (kvm_read_guest_page_mmu(vcpu, mmu, table_gfn,&pte, > > - offset, sizeof(pte), > > - PFERR_USER_MASK|PFERR_WRITE_MASK)) { > > + if (FNAME(read_guest_pte)(vcpu, mmu, table_gfn, offset,&pte)) { > > present = false; > > break; > > } > > > I think it's better to avoid a separate function for this. The reason > is I'd like to use ptep_user for cmpxchg_gpte() later on in > walk_addr_generic(), so we use the same calculation for both read and > write. So please just inline the new code in walk_addr_generic(). > > In fact there's probably a bug there for nested npt - we use > gfn_to_page(table_gfn), but table_gfn is actually an ngfn, not a gfn. > Joerg, am I right here?This patch seems only to introduce another wrapper around kvm_read_guest_page_mmu(), so I don't see a problem in this patch.
By patch 3, ptep_user will be computed in this function and no longer available for setting the accessed bit later on.
The kvm_read_guest_page_mmu takes care whether it gets a l1-gfn or l2-gfn (by calling mmu->translate_gpa).
But cmpxchg_gpte() does not. -- error compiling committee.c: too many arguments to function -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
