On 08.10.2020 17:15, Roger Pau Monné wrote:
> On Wed, Sep 16, 2020 at 03:08:40PM +0200, Jan Beulich wrote:
>> +void shadow_vram_put_mfn(mfn_t mfn, unsigned int l1f,
>> + mfn_t sl1mfn, const void *sl1e,
>> + const struct domain *d)
>> +{
>> + unsigned long gfn;
>> + struct sh_dirty_vram *dirty_vram = d->arch.hvm.dirty_vram;
>> +
>> + ASSERT(is_hvm_domain(d));
>> +
>> + if ( !dirty_vram /* tracking disabled? */ ||
>> + !(l1f & _PAGE_RW) /* read-only mapping? */ ||
>> + !mfn_valid(mfn) /* mfn can be invalid in mmio_direct */)
>> + return;
>> +
>> + gfn = gfn_x(mfn_to_gfn(d, mfn));
>> + /* Page sharing not supported on shadow PTs */
>> + BUG_ON(SHARED_M2P(gfn));
>> +
>> + if ( (gfn >= dirty_vram->begin_pfn) && (gfn < dirty_vram->end_pfn) )
>> + {
>> + unsigned long i = gfn - dirty_vram->begin_pfn;
>> + const struct page_info *page = mfn_to_page(mfn);
>> + bool dirty = false;
>> + paddr_t sl1ma = mfn_to_maddr(sl1mfn) | PAGE_OFFSET(sl1e);
>> +
>> + if ( (page->u.inuse.type_info & PGT_count_mask) == 1 )
>> + {
>> + /* Last reference */
>> + if ( dirty_vram->sl1ma[i] == INVALID_PADDR )
>> + {
>> + /* We didn't know it was that one, let's say it is dirty */
>> + dirty = true;
>> + }
>> + else
>> + {
>> + ASSERT(dirty_vram->sl1ma[i] == sl1ma);
>> + dirty_vram->sl1ma[i] = INVALID_PADDR;
>> + if ( l1f & _PAGE_DIRTY )
>> + dirty = true;
>> + }
>> + }
>> + else
>> + {
>> + /* We had more than one reference, just consider the page
>> dirty. */
>> + dirty = true;
>> + /* Check that it's not the one we recorded. */
>> + if ( dirty_vram->sl1ma[i] == sl1ma )
>> + {
>> + /* Too bad, we remembered the wrong one... */
>> + dirty_vram->sl1ma[i] = INVALID_PADDR;
>> + }
>> + else
>> + {
>> + /*
>> + * Ok, our recorded sl1e is still pointing to this page,
>> let's
>> + * just hope it will remain.
>> + */
>> + }
>> + }
>> +
>> + if ( dirty )
>> + {
>> + dirty_vram->dirty_bitmap[i / 8] |= 1 << (i % 8);
>
> Could you use _set_bit here?
In addition to what Andrew has said - this would be a non cosmetic
change, which I wouldn't want to do in a patch merely moving this
code.
>> @@ -1194,7 +1094,9 @@ static int shadow_set_l1e(struct domain
>> new_sl1e = shadow_l1e_flip_flags(new_sl1e, rc);
>> /* fall through */
>> case 0:
>> - shadow_vram_get_l1e(new_sl1e, sl1e, sl1mfn, d);
>> + shadow_vram_get_mfn(shadow_l1e_get_mfn(new_sl1e),
>> + shadow_l1e_get_flags(new_sl1e),
>> + sl1mfn, sl1e, d);
>
> As you have moved this function into a HVM build time file, don't you
> need to guard this call, or alternatively provide a dummy handler for
> !CONFIG_HVM in private.h?
>
> Same for shadow_vram_put_mfn.
All uses are inside conditionals using shadow_mode_refcounts(), i.e.
the compiler's DCE pass will eliminate the calls. All we need are
declarations to be in scope.
Jan
