| Message ID | 20170814142418.13267-25-julien.grall@arm.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
Hi, On 14/08/17 15:24, Julien Grall wrote: > Currently, the flags used to update page tables (i.e PAGE_HYPERVISOR_*) > only contains the memory attribute index. Follow-up patches will add > more information in it. > > At the same time introduce PAGE_AI_MASK to get the memory attribute > index easily. > > Signed-off-by: Julien Grall <julien.grall@arm.com> I wonder if that should be merged with the next patch, to explain the reason for it. As it stands now it just applies a mask to some existing call, which looks a bit suspicious. But that's just a nit and the patch itself is fine, so: Reviewed-by: Andre Przywara <andre.przywara@arm.com> Cheers, Andre. > --- > xen/arch/arm/mm.c | 2 +- > xen/include/asm-arm/page.h | 7 +++++++ > 2 files changed, 8 insertions(+), 1 deletion(-) > > diff --git a/xen/arch/arm/mm.c b/xen/arch/arm/mm.c > index 411fe02842..cd7bcf7aca 100644 > --- a/xen/arch/arm/mm.c > +++ b/xen/arch/arm/mm.c > @@ -1021,7 +1021,7 @@ static int create_xen_entries(enum xenmap_operation op, > } > if ( op == RESERVE ) > break; > - pte = mfn_to_xen_entry(mfn, flags); > + pte = mfn_to_xen_entry(mfn, PAGE_AI_MASK(flags)); > pte.pt.table = 1; > write_pte(entry, pte); > break; > diff --git a/xen/include/asm-arm/page.h b/xen/include/asm-arm/page.h > index d9dac92e73..1bf8e9d012 100644 > --- a/xen/include/asm-arm/page.h > +++ b/xen/include/asm-arm/page.h > @@ -63,6 +63,13 @@ > #define MAIR0VAL (MAIRVAL & 0xffffffff) > #define MAIR1VAL (MAIRVAL >> 32) > > +/* > + * Layout of the flags used for updating the hypervisor page tables > + * > + * [0:2] Memory Attribute Index > + */ > +#define PAGE_AI_MASK(x) ((x) & 0x7U) > + > #define PAGE_HYPERVISOR (MT_NORMAL) > #define PAGE_HYPERVISOR_NOCACHE (MT_DEVICE_nGnRE) > #define PAGE_HYPERVISOR_WC (MT_NORMAL_NC) >
On 08/23/2017 03:08 PM, Andre Przywara wrote: > Hi, > > On 14/08/17 15:24, Julien Grall wrote: >> Currently, the flags used to update page tables (i.e PAGE_HYPERVISOR_*) >> only contains the memory attribute index. Follow-up patches will add >> more information in it. >> >> At the same time introduce PAGE_AI_MASK to get the memory attribute >> index easily. >> >> Signed-off-by: Julien Grall <julien.grall@arm.com> > > I wonder if that should be merged with the next patch, to explain the > reason for it. As it stands now it just applies a mask to some existing > call, which looks a bit suspicious. > But that's just a nit and the patch itself is fine, so: Not really it just documents the current behavior rather than hiding what is going on. Cheers, > > Reviewed-by: Andre Przywara <andre.przywara@arm.com> > > Cheers, > Andre. > >> --- >> xen/arch/arm/mm.c | 2 +- >> xen/include/asm-arm/page.h | 7 +++++++ >> 2 files changed, 8 insertions(+), 1 deletion(-) >> >> diff --git a/xen/arch/arm/mm.c b/xen/arch/arm/mm.c >> index 411fe02842..cd7bcf7aca 100644 >> --- a/xen/arch/arm/mm.c >> +++ b/xen/arch/arm/mm.c >> @@ -1021,7 +1021,7 @@ static int create_xen_entries(enum xenmap_operation op, >> } >> if ( op == RESERVE ) >> break; >> - pte = mfn_to_xen_entry(mfn, flags); >> + pte = mfn_to_xen_entry(mfn, PAGE_AI_MASK(flags)); >> pte.pt.table = 1; >> write_pte(entry, pte); >> break; >> diff --git a/xen/include/asm-arm/page.h b/xen/include/asm-arm/page.h >> index d9dac92e73..1bf8e9d012 100644 >> --- a/xen/include/asm-arm/page.h >> +++ b/xen/include/asm-arm/page.h >> @@ -63,6 +63,13 @@ >> #define MAIR0VAL (MAIRVAL & 0xffffffff) >> #define MAIR1VAL (MAIRVAL >> 32) >> >> +/* >> + * Layout of the flags used for updating the hypervisor page tables >> + * >> + * [0:2] Memory Attribute Index >> + */ >> +#define PAGE_AI_MASK(x) ((x) & 0x7U) >> + >> #define PAGE_HYPERVISOR (MT_NORMAL) >> #define PAGE_HYPERVISOR_NOCACHE (MT_DEVICE_nGnRE) >> #define PAGE_HYPERVISOR_WC (MT_NORMAL_NC) >>
diff --git a/xen/arch/arm/mm.c b/xen/arch/arm/mm.c index 411fe02842..cd7bcf7aca 100644 --- a/xen/arch/arm/mm.c +++ b/xen/arch/arm/mm.c @@ -1021,7 +1021,7 @@ static int create_xen_entries(enum xenmap_operation op, } if ( op == RESERVE ) break; - pte = mfn_to_xen_entry(mfn, flags); + pte = mfn_to_xen_entry(mfn, PAGE_AI_MASK(flags)); pte.pt.table = 1; write_pte(entry, pte); break; diff --git a/xen/include/asm-arm/page.h b/xen/include/asm-arm/page.h index d9dac92e73..1bf8e9d012 100644 --- a/xen/include/asm-arm/page.h +++ b/xen/include/asm-arm/page.h @@ -63,6 +63,13 @@ #define MAIR0VAL (MAIRVAL & 0xffffffff) #define MAIR1VAL (MAIRVAL >> 32) +/* + * Layout of the flags used for updating the hypervisor page tables + * + * [0:2] Memory Attribute Index + */ +#define PAGE_AI_MASK(x) ((x) & 0x7U) + #define PAGE_HYPERVISOR (MT_NORMAL) #define PAGE_HYPERVISOR_NOCACHE (MT_DEVICE_nGnRE) #define PAGE_HYPERVISOR_WC (MT_NORMAL_NC)
Currently, the flags used to update page tables (i.e PAGE_HYPERVISOR_*) only contains the memory attribute index. Follow-up patches will add more information in it. At the same time introduce PAGE_AI_MASK to get the memory attribute index easily. Signed-off-by: Julien Grall <julien.grall@arm.com> --- xen/arch/arm/mm.c | 2 +- xen/include/asm-arm/page.h | 7 +++++++ 2 files changed, 8 insertions(+), 1 deletion(-)