Since gfn_to_page() is a sleeping function, and we want to make the core mmu
spinlocked, we need to pass the page from the walker context (which can sleep)
to the shadow context (which cannot).

[marcelo: avoid recursive locking of mmap_sem]
Signed-off-by: NAvi Kivity <avi@qumranet.com>

Do not hold kvm->lock mutex across the entire pagefault code,
only acquire it in places where it is necessary, such as mmu
hash list, active list, rmap and parent pte handling.

Allow concurrent guest walkers by switching walk_addr() to use
mmap_sem in read-mode.

And get rid of the lockless __gfn_to_page.

[avi: move kvm_mmu_pte_write() locking inside the function]
[avi: add locking for real mode]
[avi: fix cmpxchg locking]
Signed-off-by: NMarcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: NAvi Kivity <avi@qumranet.com>

Signed-off-by: NAvi Kivity <avi@qumranet.com>

Host side TLB flush can be merged together if multiple
spte need to be write-protected.
Signed-off-by: NYaozu (Eddie) Dong <eddie.dong@intel.com>
Signed-off-by: NAvi Kivity <avi@qumranet.com>

This paves the way for multiple architecture support.  Note that while
ioapic.c could potentially be shared with ia64, it is also moved.
Signed-off-by: NAvi Kivity <avi@qumranet.com>

This patches moves mmu-related fields to kvm_arch.
Signed-off-by: NZhang Xiantao <xiantao.zhang@intel.com>
Acked-by: NCarsten Otte <cotte@de.ibm.com>
Signed-off-by: NAvi Kivity <avi@qumranet.com>

Since these functions need to know the details of kvm or kvm_vcpu structure,
it can't be put in x86.h.  Create mmu.h to hold them.
Signed-off-by: NZhang Xiantao <xiantao.zhang@intel.com>
Acked-by: NCarsten Otte <cotte@de.ibm.com>
Signed-off-by: NAvi Kivity <avi@qumranet.com>

Move all the architecture-specific fields in kvm_vcpu into a new struct
kvm_vcpu_arch.
Signed-off-by: NZhang Xiantao <xiantao.zhang@intel.com>
Acked-by: NCarsten Otte <cotte@de.ibm.com>
Signed-off-by: NAvi Kivity <avi@qumranet.com>

There is a race where VCPU0 is shadowing a pagetable entry while VCPU1
is updating it, which results in a stale shadow copy.

Fix that by comparing the contents of the cached guest pte with the
current guest pte after write-protecting the guest pagetable.
Signed-off-by: NMarcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: NAvi Kivity <avi@qumranet.com>

In addition to removing some duplicated code, this also handles the unlikely
case of real-mode code updating a guest page table.  This can happen when
one vcpu (in real mode) touches a second vcpu's (in protected mode) page
tables, or if a vcpu switches to real mode, touches page tables, and switches
back.
Signed-off-by: NAvi Kivity <avi@qumranet.com>

Signed-off-by: NAvi Kivity <avi@qumranet.com>

As set_pte() no longer references either a gpte or the guest walker, we can
move it out of paging mode dependent code (which compiles twice and is
generally nasty).
Signed-off-by: NAvi Kivity <avi@qumranet.com>

When we emulate a guest pte write, we fail to apply the correct inherited
permissions from the parent ptes.  Now that we store inherited permissions
in the shadow page, we can use that to update the pte permissions correctly.
Signed-off-by: NAvi Kivity <avi@qumranet.com>

The nx bit is awkwardly placed in the 63rd bit position; furthermore it
has a reversed meaning compared to the other bits, which means we can't use
a bitwise and to calculate compounded access masks.

So, we simplify things by creating a new 3-bit exec/write/user access word,
and doing all calculations in that.
Signed-off-by: NAvi Kivity <avi@qumranet.com>

Signed-off-by: NAvi Kivity <avi@qumranet.com>

Mark guest pages as accessed when removed from the shadow page tables for
better lru processing.
Signed-off-by: NIzik Eidus <izike@qumranet.com>
Signed-off-by: NAvi Kivity <avi@qumranet.com>

Rename the awkwardly named variable.
Signed-off-by: NAvi Kivity <avi@qumranet.com>

These are traditionally named 'page', but even more traditionally, that name
is reserved for variables that point to a 'struct page'.  Rename them to 'sp'
(for "shadow page").
Signed-off-by: NAvi Kivity <avi@qumranet.com>

Converting last uses along the way.
Signed-off-by: NAvi Kivity <avi@qumranet.com>

No longer used.
Signed-off-by: NAvi Kivity <avi@qumranet.com>

Instead of passing an hpa, pass a regular struct page.
Signed-off-by: NAvi Kivity <avi@qumranet.com>

Signed-off-by: NAvi Kivity <avi@qumranet.com>

Similar information is available in the gfn parameter, so use that.
Signed-off-by: NAvi Kivity <avi@qumranet.com>

Signed-off-by: NAvi Kivity <avi@qumranet.com>

If the guest requests just a tlb flush, don't take the vm lock and
drop the mmu context pointlessly.
Signed-off-by: NAvi Kivity <avi@qumranet.com>

If all we're doing is increasing permissions on a pte (typical for demand
paging), then there's not need to flush remote tlbs.  Worst case they'll
get a spurious page fault.
Signed-off-by: NAvi Kivity <avi@qumranet.com>

Instead of incrementally changing the mmu cache size for every memory slot
operation, recalculate it from scratch.  This is simpler and safer.
Signed-off-by: NZhang Xiantao <xiantao.zhang@intel.com>
Signed-off-by: NAvi Kivity <avi@qumranet.com>

Improve dirty bit setting for pages that kvm release, until now every page
that we released we marked dirty, from now only pages that have potential
to get dirty we mark dirty.
Signed-off-by: NIzik Eidus <izike@qumranet.com>
Signed-off-by: NAvi Kivity <avi@qumranet.com>

When we map a page, we check whether some other vcpu mapped it for us and if
so, bail out.  But we should decrease the refcount on the page as we do so.
Signed-off-by: NIzik Eidus <izike@qumranet.com>
Signed-off-by: NAvi Kivity <avi@qumranet.com>

Signed-off-by: NAvi Kivity <avi@qumranet.com>

Emulation may cause a shadow pte to be instantiated, which requires
memory resources.  Make sure the caches are filled to avoid an oops.
Signed-off-by: NAvi Kivity <avi@qumranet.com>

The code that dispatches the page fault and emulates if we failed to map
is duplicated across vmx and svm.  Merge it to simplify further bugfixing.
Signed-off-by: NAvi Kivity <avi@qumranet.com>

First step to split kvm_vcpu.  Currently, we just use an macro to define
the common fields in kvm_vcpu for all archs, and all archs need to define
its own kvm_vcpu struct.
Signed-off-by: NZhang Xiantao <xiantao.zhang@intel.com>
Signed-off-by: NAvi Kivity <avi@qumranet.com>

This allows guest memory to be swapped.  Pages which are currently mapped
via shadow page tables are pinned into memory, but all other pages can
be freely swapped.

The patch makes gfn_to_page() elevate the page's reference count, and
introduces kvm_release_page() that pairs with it.
Signed-off-by: NIzik Eidus <izike@qumranet.com>
Signed-off-by: NAvi Kivity <avi@qumranet.com>

In case the page is not present in the guest memory map, return a dummy
page the guest can scribble on.

This simplifies error checking in its users.
Signed-off-by: NIzik Eidus <izike@qumranet.com>
Signed-off-by: NAvi Kivity <avi@qumranet.com>

The current kvm mmu only reverse maps writable translation.  This is used
to write-protect a page in case it becomes a pagetable.

But with swapping support, we need a reverse mapping of read-only pages as
well:  when we evict a page, we need to remove any mapping to it, whether
writable or not.
Signed-off-by: NIzik Eidus <izike@qumranet.com>
Signed-off-by: NAvi Kivity <avi@qumranet.com>

Signed-off-by: NIzik Eidus <izike@qumranet.com>
Signed-off-by: NAvi Kivity <avi@qumranet.com>

This is consistent with real-mode permissions.
Signed-off-by: NAvi Kivity <avi@qumranet.com>

This is more consistent with the accessed bit management, and makes the dirty
bit available earlier for other purposes.
Signed-off-by: NAvi Kivity <avi@qumranet.com>

This time, the biggest change is gpa_to_hpa. The translation of GPA to HPA does
not depend on the VCPU state unlike GVA to GPA so there's no need to pass in
the kvm_vcpu.
Signed-off-by: NAnthony Liguori <aliguori@us.ibm.com>
Signed-off-by: NAvi Kivity <avi@qumranet.com>