| Message ID | 1478098337-13933-1-git-send-email-andrew.cooper3@citrix.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
>>> On 02.11.16 at 15:52, <andrew.cooper3@citrix.com> wrote: > No sane OS would deliberately try this, but make Xen's emulation match real > hardware by delivering #GP(0), rather than suffering a VMEntry failure. > > Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com> Reviewed-by: Jan Beulich <jbeulich@suse.com> albeit ... > --- a/xen/arch/x86/x86_emulate/x86_emulate.c > +++ b/xen/arch/x86/x86_emulate/x86_emulate.c > @@ -4443,6 +4443,8 @@ x86_emulate( > (rc = read_ulong(ea.mem.seg, ea.mem.off+2, > &base, mode_64bit() ? 8 : 4, ctxt, ops)) ) > goto done; > + generate_exception_if(mode_64bit() && > + !is_canonical_address(base), EXC_GP, 0); ... I don't think the mode_64bit() part is needed. Jan
On 02/11/16 15:42, Jan Beulich wrote: >>>> On 02.11.16 at 15:52, <andrew.cooper3@citrix.com> wrote: >> No sane OS would deliberately try this, but make Xen's emulation match real >> hardware by delivering #GP(0), rather than suffering a VMEntry failure. >> >> Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com> > Reviewed-by: Jan Beulich <jbeulich@suse.com> > albeit ... > >> --- a/xen/arch/x86/x86_emulate/x86_emulate.c >> +++ b/xen/arch/x86/x86_emulate/x86_emulate.c >> @@ -4443,6 +4443,8 @@ x86_emulate( >> (rc = read_ulong(ea.mem.seg, ea.mem.off+2, >> &base, mode_64bit() ? 8 : 4, ctxt, ops)) ) >> goto done; >> + generate_exception_if(mode_64bit() && >> + !is_canonical_address(base), EXC_GP, 0); > ... I don't think the mode_64bit() part is needed. True - as we explicitly zero sreg to start with, the canonical base check is safe in all modes. I will drop it from v2. ~Andrew
On Wed, Nov 02, 2016 at 09:42:33AM -0600, Jan Beulich wrote: > >>> On 02.11.16 at 15:52, <andrew.cooper3@citrix.com> wrote: > > No sane OS would deliberately try this, but make Xen's emulation match real > > hardware by delivering #GP(0), rather than suffering a VMEntry failure. > > > > Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com> > > Reviewed-by: Jan Beulich <jbeulich@suse.com> Release-acked-by: Wei Liu <wei.liu2@citrix.com>
diff --git a/xen/arch/x86/x86_emulate/x86_emulate.c b/xen/arch/x86/x86_emulate/x86_emulate.c index 7a707dc..6b940c4 100644 --- a/xen/arch/x86/x86_emulate/x86_emulate.c +++ b/xen/arch/x86/x86_emulate/x86_emulate.c @@ -4443,6 +4443,8 @@ x86_emulate( (rc = read_ulong(ea.mem.seg, ea.mem.off+2, &base, mode_64bit() ? 8 : 4, ctxt, ops)) ) goto done; + generate_exception_if(mode_64bit() && + !is_canonical_address(base), EXC_GP, 0); sreg.base = base; sreg.limit = limit; if ( op_bytes == 2 )
No sane OS would deliberately try this, but make Xen's emulation match real hardware by delivering #GP(0), rather than suffering a VMEntry failure. Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com> --- CC: Jan Beulich <JBeulich@suse.com> CC: Wei Liu <wei.liu2@citrix.com> --- xen/arch/x86/x86_emulate/x86_emulate.c | 2 ++ 1 file changed, 2 insertions(+)