[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH 09/10] x86/hvm: pkeys, add pkeys support for guest_walk_tables
On 16/11/15 10:31, Huaitong Han wrote: > This patch adds pkeys support for guest_walk_tables. > > Signed-off-by: Huaitong Han <huaitong.han@xxxxxxxxx> > > diff --git a/xen/arch/x86/mm/guest_walk.c b/xen/arch/x86/mm/guest_walk.c > index 773454d..7a7ae96 100644 > --- a/xen/arch/x86/mm/guest_walk.c > +++ b/xen/arch/x86/mm/guest_walk.c > @@ -124,6 +124,46 @@ void *map_domain_gfn(struct p2m_domain *p2m, gfn_t gfn, > mfn_t *mfn, > return map; > } > > +#if GUEST_PAGING_LEVELS >= 4 > +uint32_t leaf_pte_pkeys_check(struct vcpu *vcpu, uint32_t pfec, > + uint32_t pte_access, uint32_t pte_pkeys) > +{ > + unsigned int pkru_ad, pkru_wd; > + unsigned int ff, wf, uf, rsvdf, pkuf; > + > + uf = pfec & PFEC_user_mode; > + wf = pfec & PFEC_write_access; > + rsvdf = pfec & PFEC_reserved_bit; > + ff = pfec & PFEC_insn_fetch; > + pkuf = pfec & PFEC_protection_key; > + > + if (!pkuf) > + return 0; > + > + /* > + * PKU: additional mechanism by which the paging controls > + * access to user-mode addresses based on the value in the > + * PKRU register. A fault is considered as a PKU violation if all > + * of the following conditions are ture: > + * 1.CR4_PKE=1. > + * 2.EFER_LMA=1. > + * 3.page is present with no reserved bit violations. > + * 4.the access is not an instruction fetch. > + * 5.the access is to a user page. > + * 6.PKRU.AD=1 > + * or The access is a data write and PKRU.WD=1 > + * and either CR0.WP=1 or it is a user access. > + */ Please fix the alignment of the comment. > + pkru_ad = READ_PKRU_AD(pte_pkeys); > + pkru_wd = READ_PKRU_AD(pte_pkeys); > + if ( hvm_pku_enabled(vcpu) && hvm_long_mode_enabled(vcpu) && > + !rsvdf && !ff && (pkru_ad || > + (pkru_wd && wf && (hvm_wp_enabled(vcpu) || uf)))) > + return 1; Same comments as patch 8 for the PV case. > + > + return 0; > +} > +#endif > > /* Walk the guest pagetables, after the manner of a hardware walker. */ > /* Because the walk is essentially random, it can cause a deadlock > @@ -141,6 +181,7 @@ guest_walk_tables(struct vcpu *v, struct p2m_domain *p2m, > #if GUEST_PAGING_LEVELS >= 4 /* 64-bit only... */ > guest_l3e_t *l3p = NULL; > guest_l4e_t *l4p; > + uint32_t pkeys; > #endif > uint32_t gflags, mflags, iflags, rc = 0; > bool_t smep = 0, smap = 0; > @@ -225,6 +266,7 @@ guest_walk_tables(struct vcpu *v, struct p2m_domain *p2m, > goto out; > /* Get the l3e and check its flags*/ > gw->l3e = l3p[guest_l3_table_offset(va)]; > + pkeys = guest_l3e_get_pkeys(gw->l3e); > gflags = guest_l3e_get_flags(gw->l3e) ^ iflags; > if ( !(gflags & _PAGE_PRESENT) ) { > rc |= _PAGE_PRESENT; > @@ -234,6 +276,9 @@ guest_walk_tables(struct vcpu *v, struct p2m_domain *p2m, > > pse1G = (gflags & _PAGE_PSE) && guest_supports_1G_superpages(v); > > + if (pse1G && leaf_pte_pkeys_check(v, pfec, gflags, pkeys)) > + rc |= _PAGE_PK_BIT; > + > if ( pse1G ) > { > /* Generate a fake l1 table entry so callers don't all > @@ -295,7 +340,6 @@ guest_walk_tables(struct vcpu *v, struct p2m_domain *p2m, > gw->l2e = l2p[guest_l2_table_offset(va)]; > > #endif /* All levels... */ > - Spurious deletion. > gflags = guest_l2e_get_flags(gw->l2e) ^ iflags; > if ( !(gflags & _PAGE_PRESENT) ) { > rc |= _PAGE_PRESENT; > @@ -305,6 +349,12 @@ guest_walk_tables(struct vcpu *v, struct p2m_domain *p2m, > > pse2M = (gflags & _PAGE_PSE) && guest_supports_superpages(v); > > +#if GUEST_PAGING_LEVELS >= 4 > + pkeys = guest_l2e_get_pkeys(gw->l2e); > + if (pse2M && leaf_pte_pkeys_check(v, pfec, gflags, pkeys)) > + rc |= _PAGE_PK_BIT; > +#endif > + > if ( pse2M ) > { > /* Special case: this guest VA is in a PSE superpage, so there's > @@ -365,6 +415,11 @@ guest_walk_tables(struct vcpu *v, struct p2m_domain *p2m, > goto out; > } > rc |= ((gflags & mflags) ^ mflags); > +#if GUEST_PAGING_LEVELS >= 4 > + pkeys = guest_l1e_get_pkeys(gw->l1e); > + if (leaf_pte_pkeys_check(v, pfec, gflags, pkeys)) > + rc |= _PAGE_PK_BIT; > +#endif Without modifying the caller's logic, setting _PAGE_PK_BIT in the return value isn't going to get propagated to the guest correctly. ~Andrew _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx http://lists.xen.org/xen-devel
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