|
[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel][PATCH] Intel EPT 1GB large page support
At 03:20 +0000 on 23 Feb (1266895248), Xu, Dongxiao wrote:
> EPT: 1GB large page support.
>
> Alloc 1GB large page for EPT if possible. It also contains the logic to split
> large page into small ones (2M or 4k).
>
> Signed-off-by: Dongxiao Xu <dongxiao.xu@xxxxxxxxx>
> Signed-off-by: Xiaohui Xin <xiaohui.xin@xxxxxxxxx>
> diff -r af2a0ed32ad5 xen/arch/x86/mm/hap/p2m-ept.c
> --- a/xen/arch/x86/mm/hap/p2m-ept.c Sat Feb 20 19:25:07 2010 +0800
> +++ b/xen/arch/x86/mm/hap/p2m-ept.c Sat Feb 20 19:43:49 2010 +0800
> @@ -183,17 +239,21 @@ ept_set_entry(struct domain *d, unsigned
> int i;
> int rv = 0;
> int ret = 0;
> + int split_level = 0;
> int walk_level = order / EPT_TABLE_ORDER;
> int direct_mmio = (p2mt == p2m_mmio_direct);
> uint8_t ipat = 0;
> int need_modify_vtd_table = 1;
>
> - /* We only support 4k and 2m pages now */
> - BUG_ON(order && order != EPT_TABLE_ORDER);
> + /* We support 4K, 2M, and 1G pages now */
> + BUG_ON(order % EPT_TABLE_ORDER);
So order 27 allocations are OK? :) Actually, now that I'm looking at
this BUG_ON, I can't see why it should be true even before this
change. Is it enforced anywhere?
> if ( order != 0 )
> if ( (gfn & ((1UL << order) - 1)) )
> return 1;
> +
> + if ( order == 18 )
> + printk(KERN_INFO "Got 1GB EPT entry.\n");
Definitely not.
> table = map_domain_page(mfn_x(pagetable_get_mfn(d->arch.phys_table)));
>
> @@ -208,15 +268,21 @@ ept_set_entry(struct domain *d, unsigned
> break;
> }
>
> - /* If order == 9, we should never get SUPERPAGE or PoD.
> + /* If order == 9 or 18, we should never get SUPERPAGE or PoD.
Why is that true? Surely having introduced order-18 entries you can
now get SUPERPAGE when asking for an order-9 entry.
> * If order == 0, we should only get POD if we have a POD superpage.
> * If i > walk_level, we need to split the page; otherwise,
> * just behave as normal. */
> ASSERT(order == 0 || ret == GUEST_TABLE_NORMAL_PAGE);
> ASSERT(ret != GUEST_TABLE_POD_PAGE || i != walk_level);
>
> + if ( i && i == walk_level && i <= cpu_vmx_ept_super_page_level_limit
> + && ret == GUEST_TABLE_NORMAL_PAGE )
> + ret = GUEST_TABLE_SUPER_PAGE;
> +
That needs a comment explaining it.
> index = gfn_remainder >> ( i ? (i * EPT_TABLE_ORDER): order);
> offset = (gfn_remainder & ( ((1 << (i*EPT_TABLE_ORDER)) - 1)));
> +
> + split_level = i;
>
> ept_entry = table + index;
>
> @@ -240,7 +306,7 @@ ept_set_entry(struct domain *d, unsigned
>
> if ( (ept_entry->avail1 == p2m_ram_logdirty)
> && (p2mt == p2m_ram_rw) )
> - for ( i = 0; i < 512; i++ )
> + for ( i = 0; i < (1UL << order); i++ )
Gosh. What's the performance of *that* like on live migration?
> paging_mark_dirty(d, mfn_x(mfn) - offset + i);
> }
> else
> @@ -261,51 +327,22 @@ ept_set_entry(struct domain *d, unsigned
> }
> else
> {
> - /*
> - * It's super page before, now set one of the 4k pages, so
> - * we should split the 2m page to 4k pages now.
> - */
> - /* Pointers to / into new (split) middle-level table */
> - ept_entry_t *split_table = NULL;
> - ept_entry_t *split_ept_entry = NULL;
> - /* Info about old (superpage) table */
> - unsigned long super_mfn = ept_entry->mfn;
> - p2m_type_t super_p2mt = ept_entry->avail1;
> - /* The new l2 entry which we'll write after we've build the new l1
> table */
> - ept_entry_t l2_ept_entry;
> -
> - /*
> - * Allocate new page for new ept middle level entry which is
> - * before a leaf super entry
> - */
> - if ( !ept_set_middle_entry(d, &l2_ept_entry) )
> - goto out;
> -
> - /* Split the super page before to 4k pages */
> - split_table = map_domain_page(l2_ept_entry.mfn);
> - offset = gfn & ((1 << EPT_TABLE_ORDER) - 1);
> -
> - for ( i = 0; i < 512; i++ )
> - {
> - split_ept_entry = split_table + i;
> - split_ept_entry->emt = epte_get_entry_emt(d, gfn - offset + i,
> - _mfn(super_mfn + i),
> - &ipat, direct_mmio);
> - split_ept_entry->ipat = ipat;
> - split_ept_entry->sp_avail = 0;
> - /* Don't increment mfn if it's a PoD mfn */
> - if ( super_p2mt != p2m_populate_on_demand )
> - split_ept_entry->mfn = super_mfn + i;
> - else
> - split_ept_entry->mfn = super_mfn;
> - split_ept_entry->avail1 = super_p2mt;
> - split_ept_entry->avail2 = 0;
> -
> - ept_p2m_type_to_flags(split_ept_entry, super_p2mt);
> - }
> -
> - /* Set the destinated 4k page as normal */
> - split_ept_entry = split_table + offset;
> + int num = order / EPT_TABLE_ORDER;
> + int level;
> + ept_entry_t *split_ept_entry;
> +
> + if ( num >= cpu_vmx_ept_super_page_level_limit )
> + num = cpu_vmx_ept_super_page_level_limit;
> + for ( level = split_level; level > num ; level-- )
> + {
> + rv = ept_split_large_page(d, &table, &index, gfn, level);
> + if ( !rv )
> + goto out;
> + }
> +
> + split_ept_entry = table + index;
> + split_ept_entry->avail1 = p2mt;
> + ept_p2m_type_to_flags(split_ept_entry, p2mt);
> split_ept_entry->emt = epte_get_entry_emt(d, gfn, mfn, &ipat,
> direct_mmio);
> split_ept_entry->ipat = ipat;
> @@ -314,12 +351,6 @@ ept_set_entry(struct domain *d, unsigned
> need_modify_vtd_table = 0;
> else
> split_ept_entry->mfn = mfn_x(mfn);
> -
> - split_ept_entry->avail1 = p2mt;
> - ept_p2m_type_to_flags(split_ept_entry, p2mt);
> -
> - unmap_domain_page(split_table);
> - *ept_entry = l2_ept_entry;
> }
>
> /* Track the highest gfn for which we have ever had a valid mapping */
> @@ -336,7 +367,7 @@ out:
> ept_sync_domain(d);
>
> /* Now the p2m table is not shared with vt-d page table */
> - if ( iommu_enabled && need_iommu(d) && need_modify_vtd_table )
> + if ( rv && iommu_enabled && need_iommu(d) && need_modify_vtd_table )
> {
> if ( p2mt == p2m_ram_rw )
> {
> @@ -459,7 +490,7 @@ out:
> /* WARNING: Only caller doesn't care about PoD pages. So this function will
> * always return 0 for PoD pages, not populate them. If that becomes
> necessary,
> * pass a p2m_query_t type along to distinguish. */
> -static ept_entry_t ept_get_entry_content(struct domain *d, unsigned long gfn)
> +static ept_entry_t ept_get_entry_content(struct domain *d, unsigned long
> gfn, int *level)
> {
> ept_entry_t *table =
> map_domain_page(mfn_x(pagetable_get_mfn(d->arch.phys_table)));
> @@ -487,6 +518,7 @@ static ept_entry_t ept_get_entry_content
> index = gfn_remainder >> (i * EPT_TABLE_ORDER);
> ept_entry = table + index;
> content = *ept_entry;
> + *level = i;
>
> out:
> unmap_domain_page(table);
> @@ -579,7 +611,10 @@ void ept_change_entry_emt_with_range(str
> p2m_lock(d->arch.p2m);
> for ( gfn = start_gfn; gfn <= end_gfn; gfn++ )
> {
> - e = ept_get_entry_content(d, gfn);
> + int level = 0;
> + uint64_t trunk = 0;
> +
> + e = ept_get_entry_content(d, gfn, &level);
> if ( !p2m_has_emt(e.avail1) )
> continue;
>
> @@ -588,25 +623,23 @@ void ept_change_entry_emt_with_range(str
>
> if ( e.sp_avail )
> {
> - if ( !(gfn & ((1 << EPT_TABLE_ORDER) - 1)) &&
> - ((gfn + 0x1FF) <= end_gfn) )
> + while ( level )
> {
> - /*
> - * gfn assigned with 2M, and the end covers more than 2m
> areas.
> - * Set emt for super page.
> - */
> - order = EPT_TABLE_ORDER;
> - if ( need_modify_ept_entry(d, gfn, mfn, e.ipat, e.emt,
> e.avail1) )
> - ept_set_entry(d, gfn, mfn, order, e.avail1);
> - gfn += 0x1FF;
> - }
> - else
> - {
> - /* Change emt for partial entries of the 2m area. */
> - if ( need_modify_ept_entry(d, gfn, mfn, e.ipat, e.emt,
> e.avail1) )
> - ept_set_entry(d, gfn, mfn, order, e.avail1);
> - gfn = ((gfn >> EPT_TABLE_ORDER) << EPT_TABLE_ORDER) + 0x1FF;
> - }
> + trunk = (1UL << (level * EPT_TABLE_ORDER)) - 1;
> + if ( !(gfn & trunk) && (gfn + trunk <= end_gfn) )
> + {
> + /* gfn assigned with 2M, and the end covers more than 2m
> areas.
This code covers 2M and 1G superpages; please fix the comment too.
> + * Set emt for super page.
> + */
> + order = level * EPT_TABLE_ORDER;
> + if ( need_modify_ept_entry(d, gfn, mfn,
> + e.ipat, e.emt, e.avail1) )
> + ept_set_entry(d, gfn, mfn, order, e.avail1);
> + gfn += trunk;
> + break;
> + }
> + level--;
> + }
> }
> else /* gfn assigned with 4k */
> {
Cheers,
Tim.
--
Tim Deegan <Tim.Deegan@xxxxxxxxxx>
Principal Software Engineer, XenServer Engineering
Citrix Systems UK Ltd. (Company #02937203, SL9 0BG)
_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxx
http://lists.xensource.com/xen-devel
|
 |
Lists.xenproject.org is hosted with RackSpace, monitoring our |