Message ID | 20161104153358.mljzjiqans52he6e@mac (mailing list archive) |
---|---|
State | New, archived |
Headers | show |
>>> On 04.11.16 at 16:33, <roger.pau@citrix.com> wrote: > --- a/xen/include/asm-x86/p2m.h > +++ b/xen/include/asm-x86/p2m.h > @@ -834,6 +834,7 @@ static inline unsigned int p2m_get_iommu_flags(p2m_type_t p2mt) > case p2m_grant_map_rw: > case p2m_ram_logdirty: > case p2m_map_foreign: > + case p2m_mmio_direct: > flags = IOMMUF_readable | IOMMUF_writable; > break; > case p2m_ram_ro: Generally this may be the route to go. But if we want to do so, we need to throughly understand why this type wasn't included here before (and I don't know myself). Jan
On Fri, Nov 04, 2016 at 10:13:08AM -0600, Jan Beulich wrote: > >>> On 04.11.16 at 16:33, <roger.pau@citrix.com> wrote: > > --- a/xen/include/asm-x86/p2m.h > > +++ b/xen/include/asm-x86/p2m.h > > @@ -834,6 +834,7 @@ static inline unsigned int p2m_get_iommu_flags(p2m_type_t p2mt) > > case p2m_grant_map_rw: > > case p2m_ram_logdirty: > > case p2m_map_foreign: > > + case p2m_mmio_direct: > > flags = IOMMUF_readable | IOMMUF_writable; > > break; > > case p2m_ram_ro: > > Generally this may be the route to go. But if we want to do so, we > need to throughly understand why this type wasn't included here > before (and I don't know myself). It was me that introduced p2m_get_iommu_flags, and I just didn't think it would be useful at that point, that's why it wasn't included. The patch that introduced p2m_get_iommu_flags was focused on fixing DMA'ing from grant-pages on HVM guests with passed-through hardware, this was needed for driver domains and later on by classic PVH Dom0 Roger.
>>> On 04.11.16 at 17:19, <roger.pau@citrix.com> wrote: > On Fri, Nov 04, 2016 at 10:13:08AM -0600, Jan Beulich wrote: >> >>> On 04.11.16 at 16:33, <roger.pau@citrix.com> wrote: >> > --- a/xen/include/asm-x86/p2m.h >> > +++ b/xen/include/asm-x86/p2m.h >> > @@ -834,6 +834,7 @@ static inline unsigned int p2m_get_iommu_flags(p2m_type_t p2mt) >> > case p2m_grant_map_rw: >> > case p2m_ram_logdirty: >> > case p2m_map_foreign: >> > + case p2m_mmio_direct: >> > flags = IOMMUF_readable | IOMMUF_writable; >> > break; >> > case p2m_ram_ro: >> >> Generally this may be the route to go. But if we want to do so, we >> need to throughly understand why this type wasn't included here >> before (and I don't know myself). > > It was me that introduced p2m_get_iommu_flags, and I just didn't think it > would be useful at that point, that's why it wasn't included. But there must have been logic to set the permissions before that? Jan
On Fri, Nov 04, 2016 at 11:08:21AM -0600, Jan Beulich wrote: > >>> On 04.11.16 at 17:19, <roger.pau@citrix.com> wrote: > > On Fri, Nov 04, 2016 at 10:13:08AM -0600, Jan Beulich wrote: > >> >>> On 04.11.16 at 16:33, <roger.pau@citrix.com> wrote: > >> > --- a/xen/include/asm-x86/p2m.h > >> > +++ b/xen/include/asm-x86/p2m.h > >> > @@ -834,6 +834,7 @@ static inline unsigned int p2m_get_iommu_flags(p2m_type_t p2mt) > >> > case p2m_grant_map_rw: > >> > case p2m_ram_logdirty: > >> > case p2m_map_foreign: > >> > + case p2m_mmio_direct: > >> > flags = IOMMUF_readable | IOMMUF_writable; > >> > break; > >> > case p2m_ram_ro: > >> > >> Generally this may be the route to go. But if we want to do so, we > >> need to throughly understand why this type wasn't included here > >> before (and I don't know myself). > > > > It was me that introduced p2m_get_iommu_flags, and I just didn't think it > > would be useful at that point, that's why it wasn't included. > > But there must have been logic to set the permissions before that? Previous to that only p2m_ram_rw would get IOMMU mappings. I've tracked this back to ff635e12, but there's no mention there about why only p2m_ram_rw would get IOMMU mappings. Considering that on hw with shared page-tables this is already available, I don't see an issue with also doing it for the non-shared pt case. Roger.
>>> On 04.11.16 at 18:25, <roger.pau@citrix.com> wrote: > On Fri, Nov 04, 2016 at 11:08:21AM -0600, Jan Beulich wrote: >> >>> On 04.11.16 at 17:19, <roger.pau@citrix.com> wrote: >> > On Fri, Nov 04, 2016 at 10:13:08AM -0600, Jan Beulich wrote: >> >> >>> On 04.11.16 at 16:33, <roger.pau@citrix.com> wrote: >> >> > --- a/xen/include/asm-x86/p2m.h >> >> > +++ b/xen/include/asm-x86/p2m.h >> >> > @@ -834,6 +834,7 @@ static inline unsigned int > p2m_get_iommu_flags(p2m_type_t p2mt) >> >> > case p2m_grant_map_rw: >> >> > case p2m_ram_logdirty: >> >> > case p2m_map_foreign: >> >> > + case p2m_mmio_direct: >> >> > flags = IOMMUF_readable | IOMMUF_writable; >> >> > break; >> >> > case p2m_ram_ro: >> >> >> >> Generally this may be the route to go. But if we want to do so, we >> >> need to throughly understand why this type wasn't included here >> >> before (and I don't know myself). >> > >> > It was me that introduced p2m_get_iommu_flags, and I just didn't think it >> > would be useful at that point, that's why it wasn't included. >> >> But there must have been logic to set the permissions before that? > > Previous to that only p2m_ram_rw would get IOMMU mappings. I've tracked this > back to ff635e12, but there's no mention there about why only p2m_ram_rw > would get IOMMU mappings. > > Considering that on hw with shared page-tables this is already available, I > don't see an issue with also doing it for the non-shared pt case. True. Jan
diff --git a/xen/arch/x86/mm/p2m.c b/xen/arch/x86/mm/p2m.c index 6a45185..7e33ab6 100644 --- a/xen/arch/x86/mm/p2m.c +++ b/xen/arch/x86/mm/p2m.c @@ -1053,16 +1053,7 @@ int set_identity_p2m_entry(struct domain *d, unsigned long gfn, ret = p2m_set_entry(p2m, gfn, _mfn(gfn), PAGE_ORDER_4K, p2m_mmio_direct, p2ma); else if ( mfn_x(mfn) == gfn && p2mt == p2m_mmio_direct && a == p2ma ) - { ret = 0; - /* - * PVH fixme: during Dom0 PVH construction, p2m entries are being set - * but iomem regions are not mapped with IOMMU. This makes sure that - * RMRRs are correctly mapped with IOMMU. - */ - if ( is_hardware_domain(d) && !iommu_use_hap_pt(d) ) - ret = iommu_map_page(d, gfn, gfn, IOMMUF_readable|IOMMUF_writable); - } else { if ( flag & XEN_DOMCTL_DEV_RDM_RELAXED ) diff --git a/xen/include/asm-x86/p2m.h b/xen/include/asm-x86/p2m.h index 7035860..b562da3 100644 --- a/xen/include/asm-x86/p2m.h +++ b/xen/include/asm-x86/p2m.h @@ -834,6 +834,7 @@ static inline unsigned int p2m_get_iommu_flags(p2m_type_t p2mt) case p2m_grant_map_rw: case p2m_ram_logdirty: case p2m_map_foreign: + case p2m_mmio_direct: flags = IOMMUF_readable | IOMMUF_writable; break;