Sign Up
Log In
Log In
or
Sign Up
Places
All Projects
Status Monitor
Collapse sidebar
openSUSE:Leap:15.0:Rings:1-MinimalX
xen
5a5cb24c-x86-mm-always-set-_PAGE_ACCESSED-on-L4...
Overview
Repositories
Revisions
Requests
Users
Attributes
Meta
File 5a5cb24c-x86-mm-always-set-_PAGE_ACCESSED-on-L4-updates.patch of Package xen
# Commit bd61fe94bee0556bc2f64999a4a8315b93f90f21 # Date 2018-01-15 13:53:16 +0000 # Author Andrew Cooper <andrew.cooper3@citrix.com> # Committer Andrew Cooper <andrew.cooper3@citrix.com> x86/mm: Always set _PAGE_ACCESSED on L4e updates Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com> Reviewed-by: Jan Beulich <jbeulich@suse.com> --- a/xen/arch/x86/pv/mm.h +++ b/xen/arch/x86/pv/mm.h @@ -144,9 +144,21 @@ static inline l3_pgentry_t unadjust_gues static inline l4_pgentry_t adjust_guest_l4e(l4_pgentry_t l4e, const struct domain *d) { - if ( likely(l4e_get_flags(l4e) & _PAGE_PRESENT) && - likely(!is_pv_32bit_domain(d)) ) - l4e_add_flags(l4e, _PAGE_USER); + /* + * When shadowing an L4 behind the guests back (e.g. for per-pcpu + * purposes), we cannot efficiently sync access bit updates from hardware + * (on the shadow tables) back into the guest view. + * + * We therefore unconditionally set _PAGE_ACCESSED even in the guests + * view. This will appear to the guest as a CPU which proactively pulls + * all valid L4e's into its TLB, which is compatible with the x86 ABI. + * + * At the time of writing, all PV guests set the access bit anyway, so + * this is no actual change in their behaviour. + */ + if ( likely(l4e_get_flags(l4e) & _PAGE_PRESENT) ) + l4e_add_flags(l4e, (_PAGE_ACCESSED | + (is_pv_32bit_domain(d) ? 0 : _PAGE_USER))); return l4e; }
Locations
Projects
Search
Status Monitor
Help
OpenBuildService.org
Documentation
API Documentation
Code of Conduct
Contact
Support
@OBShq
Terms
openSUSE Build Service is sponsored by
The Open Build Service is an
openSUSE project
.
Sign Up
Log In
Places
Places
All Projects
Status Monitor