| Message ID | 20170601151906.10213-5-proskurin@sec.in.tum.de (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
Hi Sergej, On 06/01/2017 04:18 PM, Sergej Proskurin wrote: > The current implementation does not provide appropriate types for > short-descriptor translation table entries. As such, this commit adds new > types, which simplify managing the respective translation table entries. > > Signed-off-by: Sergej Proskurin <proskurin@sec.in.tum.de> > --- > Cc: Stefano Stabellini <sstabellini@kernel.org> > Cc: Julien Grall <julien.grall@arm.com> > --- > xen/include/asm-arm/page.h | 19 +++++++++++++++++++ > 1 file changed, 19 insertions(+) > > diff --git a/xen/include/asm-arm/page.h b/xen/include/asm-arm/page.h > index 6222b1d4a2..5ea97ba95b 100644 > --- a/xen/include/asm-arm/page.h > +++ b/xen/include/asm-arm/page.h > @@ -205,6 +205,25 @@ typedef union { > lpae_walk_t walk; > } lpae_t; > > +/* > + * Comprises the bits required to walk page tables adhering to the > + * short-descriptor translation table format. > + */ > +typedef struct __packed { > + unsigned int dt:2; /* Descriptor type */ > + unsigned int pad1:8; > + unsigned int base:22; /* Base address of block or next table */ This is clearly confusing. The base address size varies with the level you are currently walking. Without looking at the code, I can guess that you would need shift/mask to adapt the base address. This is a call for providing structure for each level (there is only 2 anyway). > +} pte_sd_walk_t; I am a bit surprised this is the only bits you required for the walking as you also need to return the permissions. Looking at the patch doing the implement in patch #7, there is a lot of hardcoding value. This is a call for a better structure definition here. > +/* > + * Represents page table entries adhering to the short-descriptor translation > + * table format. > + */ > +typedef union { > + uint32_t bits; > + pte_sd_walk_t walk; > +} pte_sd_t; > + > /* Standard entry type that we'll use to build Xen's own pagetables. > * We put the same permissions at every level, because they're ignored > * by the walker in non-leaf entries. */ > Cheers,
diff --git a/xen/include/asm-arm/page.h b/xen/include/asm-arm/page.h index 6222b1d4a2..5ea97ba95b 100644 --- a/xen/include/asm-arm/page.h +++ b/xen/include/asm-arm/page.h @@ -205,6 +205,25 @@ typedef union { lpae_walk_t walk; } lpae_t; +/* + * Comprises the bits required to walk page tables adhering to the + * short-descriptor translation table format. + */ +typedef struct __packed { + unsigned int dt:2; /* Descriptor type */ + unsigned int pad1:8; + unsigned int base:22; /* Base address of block or next table */ +} pte_sd_walk_t; + +/* + * Represents page table entries adhering to the short-descriptor translation + * table format. + */ +typedef union { + uint32_t bits; + pte_sd_walk_t walk; +} pte_sd_t; + /* Standard entry type that we'll use to build Xen's own pagetables. * We put the same permissions at every level, because they're ignored * by the walker in non-leaf entries. */
The current implementation does not provide appropriate types for short-descriptor translation table entries. As such, this commit adds new types, which simplify managing the respective translation table entries. Signed-off-by: Sergej Proskurin <proskurin@sec.in.tum.de> --- Cc: Stefano Stabellini <sstabellini@kernel.org> Cc: Julien Grall <julien.grall@arm.com> --- xen/include/asm-arm/page.h | 19 +++++++++++++++++++ 1 file changed, 19 insertions(+)