Message ID | 20170122093625.GD26526@pxdev.xzpeter.org (mailing list archive) |
---|---|
State | New, archived |
Headers | show |
On 2017年01月22日 17:36, Peter Xu wrote: > Besides this one, I tried to fix the comments in this function as > below, hope this is better (I removed 1-3 thing since I think that's > clearer from below code): > > diff --git a/hw/i386/intel_iommu.c b/hw/i386/intel_iommu.c > index e958f53..f3fe8c4 100644 > --- a/hw/i386/intel_iommu.c > +++ b/hw/i386/intel_iommu.c > @@ -735,15 +735,6 @@ static int vtd_page_walk_level(dma_addr_t addr, uint64_t start, > offset = vtd_iova_level_offset(iova, level); > slpte = vtd_get_slpte(addr, offset); > > - /* > - * When one of the following case happens, we assume the whole > - * range is invalid: > - * > - * 1. read block failed > - * 3. reserved area non-zero > - * 2. both read & write flag are not set > - */ > - > if (slpte == (uint64_t)-1) { > trace_vtd_page_walk_skip_read(iova, iova_next); > skipped_local++; > @@ -761,20 +752,16 @@ static int vtd_page_walk_level(dma_addr_t addr, uint64_t start, > write_cur = write && (slpte & VTD_SL_W); > > /* > - * As long as we have either read/write permission, this is > - * a valid entry. The rule works for both page or page tables. > + * As long as we have either read/write permission, this is a > + * valid entry. The rule works for both page entries and page > + * table entries. > */ > entry_valid = read_cur | write_cur; > > if (vtd_is_last_slpte(slpte, level)) { > entry.target_as = &address_space_memory; > entry.iova = iova & subpage_mask; > - /* > - * This might be meaningless addr if (!read_cur && > - * !write_cur), but after all this field will be > - * meaningless in that case, so let's share the code to > - * generate the IOTLBs no matter it's an MAP or UNMAP > - */ > + /* NOTE: this is only meaningful if entry_valid == true */ > entry.translated_addr = vtd_get_slpte_addr(slpte); > entry.addr_mask = ~subpage_mask; > entry.perm = IOMMU_ACCESS_FLAG(read_cur, write_cur); > > Thanks, > > -- peterx I still prefer to do this on patch 18 probably. Thanks
diff --git a/hw/i386/intel_iommu.c b/hw/i386/intel_iommu.c index e958f53..f3fe8c4 100644 --- a/hw/i386/intel_iommu.c +++ b/hw/i386/intel_iommu.c @@ -735,15 +735,6 @@ static int vtd_page_walk_level(dma_addr_t addr, uint64_t start, offset = vtd_iova_level_offset(iova, level); slpte = vtd_get_slpte(addr, offset); - /* - * When one of the following case happens, we assume the whole - * range is invalid: - * - * 1. read block failed - * 3. reserved area non-zero - * 2. both read & write flag are not set - */ - if (slpte == (uint64_t)-1) { trace_vtd_page_walk_skip_read(iova, iova_next); skipped_local++; @@ -761,20 +752,16 @@ static int vtd_page_walk_level(dma_addr_t addr, uint64_t start, write_cur = write && (slpte & VTD_SL_W); /* - * As long as we have either read/write permission, this is - * a valid entry. The rule works for both page or page tables. + * As long as we have either read/write permission, this is a + * valid entry. The rule works for both page entries and page + * table entries. */ entry_valid = read_cur | write_cur; if (vtd_is_last_slpte(slpte, level)) { entry.target_as = &address_space_memory; entry.iova = iova & subpage_mask; - /* - * This might be meaningless addr if (!read_cur && - * !write_cur), but after all this field will be - * meaningless in that case, so let's share the code to - * generate the IOTLBs no matter it's an MAP or UNMAP - */ + /* NOTE: this is only meaningful if entry_valid == true */ entry.translated_addr = vtd_get_slpte_addr(slpte); entry.addr_mask = ~subpage_mask; entry.perm = IOMMU_ACCESS_FLAG(read_cur, write_cur);