[xen master] x86/PV: drop dead paging_update_paging_modes() call during Dom0 construction

[patchbot@xxxxxxx]

commit f90a265f5b6a10f558294e4d33642868fdabc416
Author:     Jan Beulich <jbeulich@xxxxxxxx>
AuthorDate: Thu Dec 22 10:06:57 2022 +0100
Commit:     Jan Beulich <jbeulich@xxxxxxxx>
CommitDate: Thu Dec 22 10:06:57 2022 +0100

    x86/PV: drop dead paging_update_paging_modes() call during Dom0 construction
    
    The function won't ever be invoked, as paging_mode_enabled() always
    returns false here due to the immediately preceding clearing of
    d->arch.paging.mode. While compilers recognize this and eliminate the
    call, make this explicit in the source (which likely 9a28170f2da2 ["pvh
    dom0: construct_dom0 changes"] should have done right away, albeit even
    before that the call looks to have been pointless - shadow mode enabling
    has occurred later virtually forever).
    
    While there also update an adjacent partly stale comment.
    
    Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
    Reviewed-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
---
 xen/arch/x86/pv/dom0_build.c | 8 ++------
 1 file changed, 2 insertions(+), 6 deletions(-)

diff --git a/xen/arch/x86/pv/dom0_build.c b/xen/arch/x86/pv/dom0_build.c
index a62f0fa2ef..a26832ad5d 100644
--- a/xen/arch/x86/pv/dom0_build.c
+++ b/xen/arch/x86/pv/dom0_build.c
@@ -10,7 +10,6 @@
 #include <xen/init.h>
 #include <xen/libelf.h>
 #include <xen/multiboot.h>
-#include <xen/paging.h>
 #include <xen/pfn.h>
 #include <xen/sched.h>
 #include <xen/softirq.h>
@@ -804,11 +803,8 @@ int __init dom0_construct_pv(struct domain *d,
 
     d->arch.paging.mode = 0;
 
-    /* Set up CR3 value for write_ptbase */
-    if ( paging_mode_enabled(d) )
-        paging_update_paging_modes(v);
-    else
-        update_cr3(v);
+    /* Set up CR3 value for switch_cr3_cr4(). */
+    update_cr3(v);
 
     /* We run on dom0's page tables for the final part of the build process. */
     switch_cr3_cr4(cr3_pa(v->arch.cr3), read_cr4());
--
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