On 24/08/2020 13:34, Jan Beulich wrote: > --- a/xen/arch/x86/x86_64/mm.c > +++ b/xen/arch/x86/x86_64/mm.c > @@ -34,17 +34,31 @@ EMIT_FILE; > #include <asm/fixmap.h> > #include <asm/hypercall.h> > #include <asm/msr.h> > +#include <asm/pv/domain.h> > #include <asm/setup.h> > #include <asm/numa.h> > #include <asm/mem_paging.h> > #include <asm/mem_sharing.h> > #include <public/memory.h> > > +#ifdef CONFIG_PV32 > + > #define compat_machine_to_phys_mapping ((unsigned int > *)RDWR_COMPAT_MPT_VIRT_START) > > -unsigned int __read_mostly m2p_compat_vstart = > __HYPERVISOR_COMPAT_VIRT_START; > +unsigned int __initdata m2p_compat_vstart = __HYPERVISOR_COMPAT_VIRT_START; > + > +l2_pgentry_t *__read_mostly compat_idle_pg_table_l2; > + > +#else /* !CONFIG_PV32 */ > + > +/* > + * Declare the symbol such that (dead) code referencing it can be built > + * without a lot of #ifdef-ary, but mark it fully const and don't define > + * this symbol anywhere (relying on DCE by the compiler). > + */ > +extern const unsigned int *const compat_machine_to_phys_mapping;
This has a different indirection. I know it is for DCE, but it still ought to match. I'm also not convinced that asymmetric const is a good idea. All it will do is confuse people, because now the "failed to DCE" error will be a compiler error for writing to a read-only array, not a link time error like every other instance of failed DCE. Therefore, it ought to be: extern unsigned int compat_machine_to_phys_mapping[]; Otherwise, Acked-by: Andrew Cooper <andrew.coop...@citrix.com> I'm disappointed that HYPERVISOR_COMPAT_VIRT_START() hasn't disappeared, and instead sprouted a nop wrapper, but I guess it can wait for subsequent cleanup. ~Andrew
