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x86/shadow: don't use #if in unlikely() invocation
As per the standard this is UB, i.e. we're building on an extension in the compilers we use (for gcc, see "The C Preprocessor" section "Directives Within Macro Arguments"). Misra C:2012 rule 20.6 disallows this altogether, though. Combine the fix with some tidying: Fold the two level-1 checks, adjust in particular comment style, and move the unlikely() use to a single inner part of the conditional. No functional change intended. Reported-by: Andrew Cooper <andrew.cooper3@citrix.com> Signed-off-by: Jan Beulich <jbeulich@suse.com> Acked-by: Andrew Cooper <andrew.cooper3@citrix.com>
This commit is contained in:
Jan Beulich committed
1 parent
481d31a679
commit
79a53b6f6e
1 file changed
+28
-27
@@ -634,35 +634,36 @@ _sh_propagate(struct vcpu *v,
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sflags |= _PAGE_UC;
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}
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// protect guest page tables
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//
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if ( unlikely((level == 1)
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&& sh_mfn_is_a_page_table(target_mfn)
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#if (SHADOW_OPTIMIZATIONS & SHOPT_OUT_OF_SYNC )
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/* Unless the page is out of sync and the guest is
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writing to it. */
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&& !(mfn_oos_may_write(target_mfn)
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&& (ft == ft_demand_write))
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#endif /* OOS */
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) )
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sflags &= ~_PAGE_RW;
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/*
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* shadow_mode_log_dirty support
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*
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* Only allow the guest write access to a page a) on a demand fault,
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* or b) if the page is already marked as dirty.
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*
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* (We handle log-dirty entirely inside the shadow code, without using the
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* p2m_ram_logdirty p2m type: only HAP uses that.)
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*/
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if ( level == 1 && unlikely(paging_mode_log_dirty(d)) && !mmio_mfn )
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if ( level == 1 )
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{
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if ( ft & FETCH_TYPE_WRITE )
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paging_mark_dirty(d, target_mfn);
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else if ( (sflags & _PAGE_RW) &&
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!paging_mfn_is_dirty(d, target_mfn) )
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/* Protect guest page tables. */
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if ( unlikely(sh_mfn_is_a_page_table(target_mfn))
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#if SHADOW_OPTIMIZATIONS & SHOPT_OUT_OF_SYNC
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/*
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* Unless the page is out of sync and the guest is writing to it.
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*/
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&& (ft != ft_demand_write || !mfn_oos_may_write(target_mfn))
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#endif /* OOS */
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)
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sflags &= ~_PAGE_RW;
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/*
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* shadow_mode_log_dirty support
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*
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* Only allow the guest write access to a page a) on a demand fault,
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* or b) if the page is already marked as dirty.
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*
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* (We handle log-dirty entirely inside the shadow code, without using
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* the p2m_ram_logdirty p2m type: only HAP uses that.)
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*/
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if ( unlikely(paging_mode_log_dirty(d)) && !mmio_mfn )
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{
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if ( ft & FETCH_TYPE_WRITE )
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paging_mark_dirty(d, target_mfn);
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else if ( (sflags & _PAGE_RW) &&
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!paging_mfn_is_dirty(d, target_mfn) )
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sflags &= ~_PAGE_RW;
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}
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}
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// PV guests in 64-bit mode use two different page tables for user vs
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