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Message-ID: <20100201141804.GD16236@amd.com>
Date: Mon, 1 Feb 2010 15:18:04 +0100
From: Joerg Roedel <joerg.roedel@....com>
To: Joerg Roedel <joro@...tes.org>
CC: Marcelo Tosatti <mtosatti@...hat.com>, Avi Kivity <avi@...hat.com>,
David Woodhouse <dwmw2@...radead.org>, kvm@...r.kernel.org,
iommu@...ts.linux-foundation.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 06/11] kvm: Change kvm_iommu_map_pages to map large
pages
On Fri, Jan 29, 2010 at 10:32:33AM +0100, Joerg Roedel wrote:
> On Thu, Jan 28, 2010 at 08:24:55PM -0200, Marcelo Tosatti wrote:
> > On Thu, Jan 28, 2010 at 12:37:57PM +0100, Joerg Roedel wrote:
> > > +static pfn_t kvm_pin_pages(struct kvm *kvm, struct kvm_memory_slot *slot,
> > > + gfn_t gfn, unsigned long size)
> > > +{
> > > + gfn_t end_gfn;
> > > + pfn_t pfn;
> > > +
> > > + pfn = gfn_to_pfn_memslot(kvm, slot, gfn);
> >
> > If gfn_to_pfn_memslot returns pfn of bad_page, you might create a
> > large iommu translation for it?
>
> Right. But that was broken even before this patch. Anyway, I will fix
> it.
>
> > > + /* Map into IO address space */
> > > + r = iommu_map(domain, gfn_to_gpa(gfn), pfn_to_hpa(pfn),
> > > + get_order(page_size), flags);
> > > +
> > > + gfn += page_size >> PAGE_SHIFT;
> >
> > Should increase gfn after checking for failure, otherwise wrong
> > npages is passed to kvm_iommu_put_pages.
>
> True. Will fix that too.
Here is the updated patch (also updated in the iommu/largepage branch of
my tree). Does it look ok?
>From fa921fe46a92dadf7f66391b519cb9ca92e2ee83 Mon Sep 17 00:00:00 2001
From: Joerg Roedel <joerg.roedel@....com>
Date: Mon, 11 Jan 2010 16:38:18 +0100
Subject: [PATCH 06/11] kvm: Change kvm_iommu_map_pages to map large pages
This patch changes the implementation of of
kvm_iommu_map_pages to map the pages with the host page size
into the io virtual address space.
Signed-off-by: Joerg Roedel <joerg.roedel@....com>
---
virt/kvm/iommu.c | 113 +++++++++++++++++++++++++++++++++++++++++++----------
1 files changed, 91 insertions(+), 22 deletions(-)
diff --git a/virt/kvm/iommu.c b/virt/kvm/iommu.c
index 65a5143..f78286e 100644
--- a/virt/kvm/iommu.c
+++ b/virt/kvm/iommu.c
@@ -32,12 +32,30 @@ static int kvm_iommu_unmap_memslots(struct kvm *kvm);
static void kvm_iommu_put_pages(struct kvm *kvm,
gfn_t base_gfn, unsigned long npages);
+static pfn_t kvm_pin_pages(struct kvm *kvm, struct kvm_memory_slot *slot,
+ gfn_t gfn, unsigned long size)
+{
+ gfn_t end_gfn;
+ pfn_t pfn;
+
+ pfn = gfn_to_pfn_memslot(kvm, slot, gfn);
+ end_gfn = gfn + (size >> PAGE_SHIFT);
+ gfn += 1;
+
+ if (is_error_pfn(pfn))
+ return pfn;
+
+ while (gfn < end_gfn)
+ gfn_to_pfn_memslot(kvm, slot, gfn++);
+
+ return pfn;
+}
+
int kvm_iommu_map_pages(struct kvm *kvm, struct kvm_memory_slot *slot)
{
- gfn_t gfn = slot->base_gfn;
- unsigned long npages = slot->npages;
+ gfn_t gfn, end_gfn;
pfn_t pfn;
- int i, r = 0;
+ int r = 0;
struct iommu_domain *domain = kvm->arch.iommu_domain;
int flags;
@@ -45,31 +63,62 @@ int kvm_iommu_map_pages(struct kvm *kvm, struct kvm_memory_slot *slot)
if (!domain)
return 0;
+ gfn = slot->base_gfn;
+ end_gfn = gfn + slot->npages;
+
flags = IOMMU_READ | IOMMU_WRITE;
if (kvm->arch.iommu_flags & KVM_IOMMU_CACHE_COHERENCY)
flags |= IOMMU_CACHE;
- for (i = 0; i < npages; i++) {
- /* check if already mapped */
- if (iommu_iova_to_phys(domain, gfn_to_gpa(gfn)))
+
+ while (gfn < end_gfn) {
+ unsigned long page_size;
+
+ /* Check if already mapped */
+ if (iommu_iova_to_phys(domain, gfn_to_gpa(gfn))) {
+ gfn += 1;
+ continue;
+ }
+
+ /* Get the page size we could use to map */
+ page_size = kvm_host_page_size(kvm, gfn);
+
+ /* Make sure the page_size does not exceed the memslot */
+ while ((gfn + (page_size >> PAGE_SHIFT)) > end_gfn)
+ page_size >>= 1;
+
+ /* Make sure gfn is aligned to the page size we want to map */
+ while ((gfn << PAGE_SHIFT) & (page_size - 1))
+ page_size >>= 1;
+
+ /*
+ * Pin all pages we are about to map in memory. This is
+ * important because we unmap and unpin in 4kb steps later.
+ */
+ pfn = kvm_pin_pages(kvm, slot, gfn, page_size);
+ if (is_error_pfn(pfn)) {
+ gfn += 1;
continue;
+ }
- pfn = gfn_to_pfn_memslot(kvm, slot, gfn);
- r = iommu_map_range(domain,
- gfn_to_gpa(gfn),
- pfn_to_hpa(pfn),
- PAGE_SIZE, flags);
+ /* Map into IO address space */
+ r = iommu_map(domain, gfn_to_gpa(gfn), pfn_to_hpa(pfn),
+ get_order(page_size), flags);
if (r) {
printk(KERN_ERR "kvm_iommu_map_address:"
"iommu failed to map pfn=%lx\n", pfn);
goto unmap_pages;
}
- gfn++;
+
+ gfn += page_size >> PAGE_SHIFT;
+
+
}
+
return 0;
unmap_pages:
- kvm_iommu_put_pages(kvm, slot->base_gfn, i);
+ kvm_iommu_put_pages(kvm, slot->base_gfn, gfn);
return r;
}
@@ -186,27 +235,47 @@ out_unmap:
return r;
}
+static void kvm_unpin_pages(struct kvm *kvm, pfn_t pfn, unsigned long npages)
+{
+ unsigned long i;
+
+ for (i = 0; i < npages; ++i)
+ kvm_release_pfn_clean(pfn + i);
+}
+
static void kvm_iommu_put_pages(struct kvm *kvm,
gfn_t base_gfn, unsigned long npages)
{
- gfn_t gfn = base_gfn;
+ struct iommu_domain *domain;
+ gfn_t end_gfn, gfn;
pfn_t pfn;
- struct iommu_domain *domain = kvm->arch.iommu_domain;
- unsigned long i;
u64 phys;
+ domain = kvm->arch.iommu_domain;
+ end_gfn = base_gfn + npages;
+ gfn = base_gfn;
+
/* check if iommu exists and in use */
if (!domain)
return;
- for (i = 0; i < npages; i++) {
+ while (gfn < end_gfn) {
+ unsigned long unmap_pages;
+ int order;
+
+ /* Get physical address */
phys = iommu_iova_to_phys(domain, gfn_to_gpa(gfn));
- pfn = phys >> PAGE_SHIFT;
- kvm_release_pfn_clean(pfn);
- gfn++;
- }
+ pfn = phys >> PAGE_SHIFT;
+
+ /* Unmap address from IO address space */
+ order = iommu_unmap(domain, gfn_to_gpa(gfn), PAGE_SIZE);
+ unmap_pages = 1ULL << order;
- iommu_unmap_range(domain, gfn_to_gpa(base_gfn), PAGE_SIZE * npages);
+ /* Unpin all pages we just unmapped to not leak any memory */
+ kvm_unpin_pages(kvm, pfn, unmap_pages);
+
+ gfn += unmap_pages;
+ }
}
static int kvm_iommu_unmap_memslots(struct kvm *kvm)
--
1.6.6
--
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