[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH v1 2/6] x86: Temporary disable SMAP to legally access user pages in kernel mode
> From: Feng Wu > Sent: Tuesday, April 15, 2014 9:02 PM > > Use STAC/CLAC to temporary disable SMAP to allow legal accesses to > user pages in kernel mode > > Signed-off-by: Feng Wu <feng.wu@xxxxxxxxx> > --- > xen/arch/x86/clear_page.S | 3 +++ > xen/arch/x86/domain_build.c | 16 ++++++++++++++++ > xen/arch/x86/usercopy.c | 6 ++++++ > xen/arch/x86/x86_64/compat/entry.S | 2 ++ > xen/arch/x86/x86_64/entry.S | 4 ++++ > xen/include/asm-x86/uaccess.h | 4 ++++ > xen/include/asm-x86/x86_64/system.h | 2 ++ > 7 files changed, 37 insertions(+) > > diff --git a/xen/arch/x86/domain_build.c b/xen/arch/x86/domain_build.c > index 84ce392..1ba138b 100644 > --- a/xen/arch/x86/domain_build.c > +++ b/xen/arch/x86/domain_build.c > @@ -789,8 +789,10 @@ int __init construct_dom0( > rc = -1; > goto out; > } > + stac(); > hypercall_page_initialise( > d, (void *)(unsigned long)parms.virt_hypercall); > + clac(); > } construct_dom0 happens before dom0 starts execution. It should be fine to keep AC cleared in the whole phase. Thanks Kevin _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx http://lists.xen.org/xen-devel
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