Commit Graph

288120 Commits

Author SHA1 Message Date
Avi Kivity
28867cee75 KVM: x86 emulator: add 8-bit memory operands
Useful for MOVSX/MOVZX.

Signed-off-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2012-03-05 14:52:42 +02:00
Scott Wood
54f65795c8 KVM: PPC: refer to paravirt docs in header file
Instead of keeping separate copies of struct kvm_vcpu_arch_shared (one in
the code, one in the docs) that inevitably fail to be kept in sync
(already sr[] is missing from the doc version), just point to the header
file as the source of documentation on the contents of the magic page.

Signed-off-by: Scott Wood <scottwood@freescale.com>
Acked-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Avi Kivity <avi@redhat.com>
2012-03-05 14:52:41 +02:00
Alexander Graf
b3c5d3c2a4 KVM: PPC: Rename MMIO register identifiers
We need the KVM_REG namespace for generic register settings now, so
let's rename the existing users to something different, enabling
us to reuse the namespace for more visible interfaces.

While at it, also move these private constants to a private header.

Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Avi Kivity <avi@redhat.com>
2012-03-05 14:52:41 +02:00
Paul Mackerras
31f3438eca KVM: PPC: Move kvm_vcpu_ioctl_[gs]et_one_reg down to platform-specific code
This moves the get/set_one_reg implementation down from powerpc.c into
booke.c, book3s_pr.c and book3s_hv.c.  This avoids #ifdefs in C code,
but more importantly, it fixes a bug on Book3s HV where we were
accessing beyond the end of the kvm_vcpu struct (via the to_book3s()
macro) and corrupting memory, causing random crashes and file corruption.

On Book3s HV we only accept setting the HIOR to zero, since the guest
runs in supervisor mode and its vectors are never offset from zero.

Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Alexander Graf <agraf@suse.de>
[agraf update to apply on top of changed ONE_REG patches]
Signed-off-by: Avi Kivity <avi@redhat.com>
2012-03-05 14:52:41 +02:00
Alexander Graf
1022fc3d3b KVM: PPC: Add support for explicit HIOR setting
Until now, we always set HIOR based on the PVR, but this is just wrong.
Instead, we should be setting HIOR explicitly, so user space can decide
what the initial HIOR value is - just like on real hardware.

We keep the old PVR based way around for backwards compatibility, but
once user space uses the SET_ONE_REG based method, we drop the PVR logic.

Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Avi Kivity <avi@redhat.com>
2012-03-05 14:52:41 +02:00
Alexander Graf
e24ed81fed KVM: PPC: Add generic single register ioctls
Right now we transfer a static struct every time we want to get or set
registers. Unfortunately, over time we realize that there are more of
these than we thought of before and the extensibility and flexibility of
transferring a full struct every time is limited.

So this is a new approach to the problem. With these new ioctls, we can
get and set a single register that is identified by an ID. This allows for
very precise and limited transmittal of data. When we later realize that
it's a better idea to shove over multiple registers at once, we can reuse
most of the infrastructure and simply implement a GET_MANY_REGS / SET_MANY_REGS
interface.

Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Avi Kivity <avi@redhat.com>
2012-03-05 14:52:40 +02:00
Sasha Levin
6b75e6bfef KVM: PPC: Use the vcpu kmem_cache when allocating new VCPUs
Currently the code kzalloc()s new VCPUs instead of using the kmem_cache
which is created when KVM is initialized.

Modify it to allocate VCPUs from that kmem_cache.

Signed-off-by: Sasha Levin <levinsasha928@gmail.com>
Acked-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Avi Kivity <avi@redhat.com>
2012-03-05 14:52:40 +02:00
Liu Yu
d37b1a037c KVM: PPC: booke: Add booke206 TLB trace
The existing kvm_stlb_write/kvm_gtlb_write were a poor match for
the e500/book3e MMU -- mas1 was passed as "tid", mas2 was limited
to "unsigned int" which will be a problem on 64-bit, mas3/7 got
split up rather than treated as a single 64-bit word, etc.

Signed-off-by: Liu Yu <yu.liu@freescale.com>
[scottwood@freescale.com: made mas2 64-bit, and added mas8 init]
Signed-off-by: Scott Wood <scottwood@freescale.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Avi Kivity <avi@redhat.com>
2012-03-05 14:52:40 +02:00
Paul Mackerras
82ed36164c KVM: PPC: Book3s HV: Implement get_dirty_log using hardware changed bit
This changes the implementation of kvm_vm_ioctl_get_dirty_log() for
Book3s HV guests to use the hardware C (changed) bits in the guest
hashed page table.  Since this makes the implementation quite different
from the Book3s PR case, this moves the existing implementation from
book3s.c to book3s_pr.c and creates a new implementation in book3s_hv.c.
That implementation calls kvmppc_hv_get_dirty_log() to do the actual
work by calling kvm_test_clear_dirty on each page.  It iterates over
the HPTEs, clearing the C bit if set, and returns 1 if any C bit was
set (including the saved C bit in the rmap entry).

Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Avi Kivity <avi@redhat.com>
2012-03-05 14:52:39 +02:00
Paul Mackerras
5551489373 KVM: PPC: Book3S HV: Use the hardware referenced bit for kvm_age_hva
This uses the host view of the hardware R (referenced) bit to speed
up kvm_age_hva() and kvm_test_age_hva().  Instead of removing all
the relevant HPTEs in kvm_age_hva(), we now just reset their R bits
if set.  Also, kvm_test_age_hva() now scans the relevant HPTEs to
see if any of them have R set.

Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Avi Kivity <avi@redhat.com>
2012-03-05 14:52:39 +02:00
Paul Mackerras
bad3b5075e KVM: PPC: Book3s HV: Maintain separate guest and host views of R and C bits
This allows both the guest and the host to use the referenced (R) and
changed (C) bits in the guest hashed page table.  The guest has a view
of R and C that is maintained in the guest_rpte field of the revmap
entry for the HPTE, and the host has a view that is maintained in the
rmap entry for the associated gfn.

Both view are updated from the guest HPT.  If a bit (R or C) is zero
in either view, it will be initially set to zero in the HPTE (or HPTEs),
until set to 1 by hardware.  When an HPTE is removed for any reason,
the R and C bits from the HPTE are ORed into both views.  We have to
be careful to read the R and C bits from the HPTE after invalidating
it, but before unlocking it, in case of any late updates by the hardware.

Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Avi Kivity <avi@redhat.com>
2012-03-05 14:52:39 +02:00
Paul Mackerras
a92bce95f0 KVM: PPC: Book3S HV: Keep HPTE locked when invalidating
This reworks the implementations of the H_REMOVE and H_BULK_REMOVE
hcalls to make sure that we keep the HPTE locked and in the reverse-
mapping chain until we have finished invalidating it.  Previously
we would remove it from the chain and unlock it before invalidating
it, leaving a tiny window when the guest could access the page even
though we believe we have removed it from the guest (e.g.,
kvm_unmap_hva() has been called for the page and has found no HPTEs
in the chain).  In addition, we'll need this for future patches where
we will need to read the R and C bits in the HPTE after invalidating
it.

Doing this required restructuring kvmppc_h_bulk_remove() substantially.
Since we want to batch up the tlbies, we now need to keep several
HPTEs locked simultaneously.  In order to avoid possible deadlocks,
we don't spin on the HPTE bitlock for any except the first HPTE in
a batch.  If we can't acquire the HPTE bitlock for the second or
subsequent HPTE, we terminate the batch at that point, do the tlbies
that we have accumulated so far, unlock those HPTEs, and then start
a new batch to do the remaining invalidations.

Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Avi Kivity <avi@redhat.com>
2012-03-05 14:52:39 +02:00
Matt Evans
b5434032fc KVM: PPC: Add KVM_CAP_NR_VCPUS and KVM_CAP_MAX_VCPUS
PPC KVM lacks these two capabilities, and as such a userland system must assume
a max of 4 VCPUs (following api.txt).  With these, a userland can determine
a more realistic limit.

Signed-off-by: Matt Evans <matt@ozlabs.org>
Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Avi Kivity <avi@redhat.com>
2012-03-05 14:52:38 +02:00
Matt Evans
03cdab5340 KVM: PPC: Fix vcpu_create dereference before validity check.
Fix usage of vcpu struct before check that it's actually valid.

Signed-off-by: Matt Evans <matt@ozlabs.org>
Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Avi Kivity <avi@redhat.com>
2012-03-05 14:52:38 +02:00
Paul Mackerras
4cf302bc10 KVM: PPC: Allow for read-only pages backing a Book3S HV guest
With this, if a guest does an H_ENTER with a read/write HPTE on a page
which is currently read-only, we make the actual HPTE inserted be a
read-only version of the HPTE.  We now intercept protection faults as
well as HPTE not found faults, and for a protection fault we work out
whether it should be reflected to the guest (e.g. because the guest HPTE
didn't allow write access to usermode) or handled by switching to
kernel context and calling kvmppc_book3s_hv_page_fault, which will then
request write access to the page and update the actual HPTE.

Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Avi Kivity <avi@redhat.com>
2012-03-05 14:52:38 +02:00
Paul Mackerras
a355aa54f1 KVM: Add barriers to allow mmu_notifier_retry to be used locklessly
This adds an smp_wmb in kvm_mmu_notifier_invalidate_range_end() and an
smp_rmb in mmu_notifier_retry() so that mmu_notifier_retry() will give
the correct answer when called without kvm->mmu_lock being held.
PowerPC Book3S HV KVM wants to use a bitlock per guest page rather than
a single global spinlock in order to improve the scalability of updates
to the guest MMU hashed page table, and so needs this.

Signed-off-by: Paul Mackerras <paulus@samba.org>
Acked-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Avi Kivity <avi@redhat.com>
2012-03-05 14:52:38 +02:00
Paul Mackerras
342d3db763 KVM: PPC: Implement MMU notifiers for Book3S HV guests
This adds the infrastructure to enable us to page out pages underneath
a Book3S HV guest, on processors that support virtualized partition
memory, that is, POWER7.  Instead of pinning all the guest's pages,
we now look in the host userspace Linux page tables to find the
mapping for a given guest page.  Then, if the userspace Linux PTE
gets invalidated, kvm_unmap_hva() gets called for that address, and
we replace all the guest HPTEs that refer to that page with absent
HPTEs, i.e. ones with the valid bit clear and the HPTE_V_ABSENT bit
set, which will cause an HDSI when the guest tries to access them.
Finally, the page fault handler is extended to reinstantiate the
guest HPTE when the guest tries to access a page which has been paged
out.

Since we can't intercept the guest DSI and ISI interrupts on PPC970,
we still have to pin all the guest pages on PPC970.  We have a new flag,
kvm->arch.using_mmu_notifiers, that indicates whether we can page
guest pages out.  If it is not set, the MMU notifier callbacks do
nothing and everything operates as before.

Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Avi Kivity <avi@redhat.com>
2012-03-05 14:52:38 +02:00
Paul Mackerras
697d3899dc KVM: PPC: Implement MMIO emulation support for Book3S HV guests
This provides the low-level support for MMIO emulation in Book3S HV
guests.  When the guest tries to map a page which is not covered by
any memslot, that page is taken to be an MMIO emulation page.  Instead
of inserting a valid HPTE, we insert an HPTE that has the valid bit
clear but another hypervisor software-use bit set, which we call
HPTE_V_ABSENT, to indicate that this is an absent page.  An
absent page is treated much like a valid page as far as guest hcalls
(H_ENTER, H_REMOVE, H_READ etc.) are concerned, except of course that
an absent HPTE doesn't need to be invalidated with tlbie since it
was never valid as far as the hardware is concerned.

When the guest accesses a page for which there is an absent HPTE, it
will take a hypervisor data storage interrupt (HDSI) since we now set
the VPM1 bit in the LPCR.  Our HDSI handler for HPTE-not-present faults
looks up the hash table and if it finds an absent HPTE mapping the
requested virtual address, will switch to kernel mode and handle the
fault in kvmppc_book3s_hv_page_fault(), which at present just calls
kvmppc_hv_emulate_mmio() to set up the MMIO emulation.

This is based on an earlier patch by Benjamin Herrenschmidt, but since
heavily reworked.

Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Avi Kivity <avi@redhat.com>
2012-03-05 14:52:37 +02:00
Paul Mackerras
06ce2c63d9 KVM: PPC: Maintain a doubly-linked list of guest HPTEs for each gfn
This expands the reverse mapping array to contain two links for each
HPTE which are used to link together HPTEs that correspond to the
same guest logical page.  Each circular list of HPTEs is pointed to
by the rmap array entry for the guest logical page, pointed to by
the relevant memslot.  Links are 32-bit HPT entry indexes rather than
full 64-bit pointers, to save space.  We use 3 of the remaining 32
bits in the rmap array entries as a lock bit, a referenced bit and
a present bit (the present bit is needed since HPTE index 0 is valid).
The bit lock for the rmap chain nests inside the HPTE lock bit.

Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Avi Kivity <avi@redhat.com>
2012-03-05 14:52:37 +02:00
Paul Mackerras
9d0ef5ea04 KVM: PPC: Allow I/O mappings in memory slots
This provides for the case where userspace maps an I/O device into the
address range of a memory slot using a VM_PFNMAP mapping.  In that
case, we work out the pfn from vma->vm_pgoff, and record the cache
enable bits from vma->vm_page_prot in two low-order bits in the
slot_phys array entries.  Then, in kvmppc_h_enter() we check that the
cache bits in the HPTE that the guest wants to insert match the cache
bits in the slot_phys array entry.  However, we do allow the guest to
create what it thinks is a non-cacheable or write-through mapping to
memory that is actually cacheable, so that we can use normal system
memory as part of an emulated device later on.  In that case the actual
HPTE we insert is a cacheable HPTE.

Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Avi Kivity <avi@redhat.com>
2012-03-05 14:52:37 +02:00
Paul Mackerras
da9d1d7f28 KVM: PPC: Allow use of small pages to back Book3S HV guests
This relaxes the requirement that the guest memory be provided as
16MB huge pages, allowing it to be provided as normal memory, i.e.
in pages of PAGE_SIZE bytes (4k or 64k).  To allow this, we index
the kvm->arch.slot_phys[] arrays with a small page index, even if
huge pages are being used, and use the low-order 5 bits of each
entry to store the order of the enclosing page with respect to
normal pages, i.e. log_2(enclosing_page_size / PAGE_SIZE).

Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Avi Kivity <avi@redhat.com>
2012-03-05 14:52:37 +02:00
Paul Mackerras
c77162dee7 KVM: PPC: Only get pages when actually needed, not in prepare_memory_region()
This removes the code from kvmppc_core_prepare_memory_region() that
looked up the VMA for the region being added and called hva_to_page
to get the pfns for the memory.  We have no guarantee that there will
be anything mapped there at the time of the KVM_SET_USER_MEMORY_REGION
ioctl call; userspace can do that ioctl and then map memory into the
region later.

Instead we defer looking up the pfn for each memory page until it is
needed, which generally means when the guest does an H_ENTER hcall on
the page.  Since we can't call get_user_pages in real mode, if we don't
already have the pfn for the page, kvmppc_h_enter() will return
H_TOO_HARD and we then call kvmppc_virtmode_h_enter() once we get back
to kernel context.  That calls kvmppc_get_guest_page() to get the pfn
for the page, and then calls back to kvmppc_h_enter() to redo the HPTE
insertion.

When the first vcpu starts executing, we need to have the RMO or VRMA
region mapped so that the guest's real mode accesses will work.  Thus
we now have a check in kvmppc_vcpu_run() to see if the RMO/VRMA is set
up and if not, call kvmppc_hv_setup_rma().  It checks if the memslot
starting at guest physical 0 now has RMO memory mapped there; if so it
sets it up for the guest, otherwise on POWER7 it sets up the VRMA.
The function that does that, kvmppc_map_vrma, is now a bit simpler,
as it calls kvmppc_virtmode_h_enter instead of creating the HPTE itself.

Since we are now potentially updating entries in the slot_phys[]
arrays from multiple vcpu threads, we now have a spinlock protecting
those updates to ensure that we don't lose track of any references
to pages.

Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Avi Kivity <avi@redhat.com>
2012-03-05 14:52:36 +02:00
Paul Mackerras
075295dd32 KVM: PPC: Make the H_ENTER hcall more reliable
At present, our implementation of H_ENTER only makes one try at locking
each slot that it looks at, and doesn't even retry the ldarx/stdcx.
atomic update sequence that it uses to attempt to lock the slot.  Thus
it can return the H_PTEG_FULL error unnecessarily, particularly when
the H_EXACT flag is set, meaning that the caller wants a specific PTEG
slot.

This improves the situation by making a second pass when no free HPTE
slot is found, where we spin until we succeed in locking each slot in
turn and then check whether it is full while we hold the lock.  If the
second pass fails, then we return H_PTEG_FULL.

This also moves lock_hpte to a header file (since later commits in this
series will need to use it from other source files) and renames it to
try_lock_hpte, which is a somewhat less misleading name.

Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Avi Kivity <avi@redhat.com>
2012-03-05 14:52:36 +02:00
Paul Mackerras
93e602490c KVM: PPC: Add an interface for pinning guest pages in Book3s HV guests
This adds two new functions, kvmppc_pin_guest_page() and
kvmppc_unpin_guest_page(), and uses them to pin the guest pages where
the guest has registered areas of memory for the hypervisor to update,
(i.e. the per-cpu virtual processor areas, SLB shadow buffers and
dispatch trace logs) and then unpin them when they are no longer
required.

Although it is not strictly necessary to pin the pages at this point,
since all guest pages are already pinned, later commits in this series
will mean that guest pages aren't all pinned.

Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Avi Kivity <avi@redhat.com>
2012-03-05 14:52:36 +02:00
Paul Mackerras
b2b2f16508 KVM: PPC: Keep page physical addresses in per-slot arrays
This allocates an array for each memory slot that is added to store
the physical addresses of the pages in the slot.  This array is
vmalloc'd and accessed in kvmppc_h_enter using real_vmalloc_addr().
This allows us to remove the ram_pginfo field from the kvm_arch
struct, and removes the 64GB guest RAM limit that we had.

We use the low-order bits of the array entries to store a flag
indicating that we have done get_page on the corresponding page,
and therefore need to call put_page when we are finished with the
page.  Currently this is set for all pages except those in our
special RMO regions.

Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Avi Kivity <avi@redhat.com>
2012-03-05 14:52:35 +02:00
Paul Mackerras
8936dda4c2 KVM: PPC: Keep a record of HV guest view of hashed page table entries
This adds an array that parallels the guest hashed page table (HPT),
that is, it has one entry per HPTE, used to store the guest's view
of the second doubleword of the corresponding HPTE.  The first
doubleword in the HPTE is the same as the guest's idea of it, so we
don't need to store a copy, but the second doubleword in the HPTE has
the real page number rather than the guest's logical page number.
This allows us to remove the back_translate() and reverse_xlate()
functions.

This "reverse mapping" array is vmalloc'd, meaning that to access it
in real mode we have to walk the kernel's page tables explicitly.
That is done by the new real_vmalloc_addr() function.  (In fact this
returns an address in the linear mapping, so the result is usable
both in real mode and in virtual mode.)

There are also some minor cleanups here: moving the definitions of
HPT_ORDER etc. to a header file and defining HPT_NPTE for HPT_NPTEG << 3.

Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Avi Kivity <avi@redhat.com>
2012-03-05 14:52:35 +02:00
Paul Mackerras
4e72dbe135 KVM: PPC: Make wakeups work again for Book3S HV guests
When commit f43fdc15fa ("KVM: PPC: booke: Improve timer register
emulation") factored out some code in arch/powerpc/kvm/powerpc.c
into a new helper function, kvm_vcpu_kick(), an error crept in
which causes Book3s HV guest vcpus to stall.  This fixes it.
On POWER7 machines, guest vcpus are grouped together into virtual
CPU cores that share a single waitqueue, so it's important to use
vcpu->arch.wqp rather than &vcpu->wq.

Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Avi Kivity <avi@redhat.com>
2012-03-05 14:52:34 +02:00
Liu Yu-B13201
befdc0a65a KVM: PPC: Avoid patching paravirt template code
Currently we patch the whole code include paravirt template code.
This isn't safe for scratch area and has impact to performance.

Signed-off-by: Liu Yu <yu.liu@freescale.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Avi Kivity <avi@redhat.com>
2012-03-05 14:52:34 +02:00
Scott Wood
570135243a KVM: PPC: e500: use hardware hint when loading TLB0 entries
The hardware maintains a per-set next victim hint.  Using this
reduces conflicts, especially on e500v2 where a single guest
TLB entry is mapped to two shadow TLB entries (user and kernel).
We want those two entries to go to different TLB ways.

sesel is now only used for TLB1.

Reported-by: Liu Yu <yu.liu@freescale.com>
Signed-off-by: Scott Wood <scottwood@freescale.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Avi Kivity <avi@redhat.com>
2012-03-05 14:52:34 +02:00
Scott Wood
7b11dc9938 KVM: PPC: e500: Fix TLBnCFG in KVM_CONFIG_TLB
The associativity, not just total size, can differ from the host
hardware.

Signed-off-by: Scott Wood <scottwood@freescale.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Avi Kivity <avi@redhat.com>
2012-03-05 14:52:32 +02:00
Alexander Graf
e371f713db KVM: PPC: Book3S: PR: Fix signal check race
As Scott put it:

> If we get a signal after the check, we want to be sure that we don't
> receive the reschedule IPI until after we're in the guest, so that it
> will cause another signal check.

we need to have interrupts disabled from the point we do signal_check()
all the way until we actually enter the guest.

This patch fixes potential signal loss races.

Reported-by: Scott Wood <scottwood@freescale.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Avi Kivity <avi@redhat.com>
2012-03-05 14:52:30 +02:00
Alexander Graf
ae21216bec KVM: PPC: align vcpu_kick with x86
Our vcpu kick implementation differs a bit from x86 which resulted in us not
disabling preemption during the kick. Get it a bit closer to what x86 does.

Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Avi Kivity <avi@redhat.com>
2012-03-05 14:52:30 +02:00
Alexander Graf
468a12c2b5 KVM: PPC: Use get/set for to_svcpu to help preemption
When running the 64-bit Book3s PR code without CONFIG_PREEMPT_NONE, we were
doing a few things wrong, most notably access to PACA fields without making
sure that the pointers stay stable accross the access (preempt_disable()).

This patch moves to_svcpu towards a get/put model which allows us to disable
preemption while accessing the shadow vcpu fields in the PACA. That way we
can run preemptible and everyone's happy!

Reported-by: Jörg Sommer <joerg@alea.gnuu.de>
Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Avi Kivity <avi@redhat.com>
2012-03-05 14:52:30 +02:00
Alexander Graf
d33ad328c0 KVM: PPC: Book3s: PR: No irq_disable in vcpu_run
Somewhere during merges we ended up from

  local_irq_enable()
  foo();
  local_irq_disable()

to always keeping irqs enabled during that part. However, we now
have the following code:

  foo();
  local_irq_disable()

which disables interrupts without the surrounding code enabling them
again! So let's remove that disable and be happy.

Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Avi Kivity <avi@redhat.com>
2012-03-05 14:52:28 +02:00
Alexander Graf
7d82714d4d KVM: PPC: Book3s: PR: Disable preemption in vcpu_run
When entering the guest, we want to make sure we're not getting preempted
away, so let's disable preemption on entry, but enable it again while handling
guest exits.

Reported-by: Jörg Sommer <joerg@alea.gnuu.de>
Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Avi Kivity <avi@redhat.com>
2012-03-05 14:52:27 +02:00
Scott Wood
dfd4d47e9a KVM: PPC: booke: Improve timer register emulation
Decrementers are now properly driven by TCR/TSR, and the guest
has full read/write access to these registers.

The decrementer keeps ticking (and setting the TSR bit) regardless of
whether the interrupts are enabled with TCR.

The decrementer stops at zero, rather than going negative.

Decrementers (and FITs, once implemented) are delivered as
level-triggered interrupts -- dequeued when the TSR bit is cleared, not
on delivery.

Signed-off-by: Liu Yu <yu.liu@freescale.com>
[scottwood@freescale.com: significant changes]
Signed-off-by: Scott Wood <scottwood@freescale.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Avi Kivity <avi@redhat.com>
2012-03-05 14:52:27 +02:00
Scott Wood
b59049720d KVM: PPC: Paravirtualize SPRG4-7, ESR, PIR, MASn
This allows additional registers to be accessed by the guest
in PR-mode KVM without trapping.

SPRG4-7 are readable from userspace.  On booke, KVM will sync
these registers when it enters the guest, so that accesses from
guest userspace will work.  The guest kernel, OTOH, must consistently
use either the real registers or the shared area between exits.  This
also applies to the already-paravirted SPRG3.

On non-booke, it's not clear to what extent SPRG4-7 are supported
(they're not architected for book3s, but exist on at least some classic
chips).  They are copied in the get/set regs ioctls, but I do not see any
non-booke emulation.  I also do not see any syncing with real registers
(in PR-mode) including the user-readable SPRG3.  This patch should not
make that situation any worse.

Signed-off-by: Scott Wood <scottwood@freescale.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Avi Kivity <avi@redhat.com>
2012-03-05 14:52:26 +02:00
Scott Wood
940b45ec18 KVM: PPC: booke: Paravirtualize wrtee
Also fix wrteei 1 paravirt to check for a pending interrupt.

Signed-off-by: Scott Wood <scottwood@freescale.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Avi Kivity <avi@redhat.com>
2012-03-05 14:52:26 +02:00
Scott Wood
29ac26efbd KVM: PPC: booke: Fix int_pending calculation for MSR[EE] paravirt
int_pending was only being lowered if a bit in pending_exceptions
was cleared during exception delivery -- but for interrupts, we clear
it during IACK/TSR emulation.  This caused paravirt for enabling
MSR[EE] to be ineffective.

Signed-off-by: Scott Wood <scottwood@freescale.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Avi Kivity <avi@redhat.com>
2012-03-05 14:52:26 +02:00
Scott Wood
c59a6a3e4e KVM: PPC: booke: Check for MSR[WE] in prepare_to_enter
This prevents us from inappropriately blocking in a KVM_SET_REGS
ioctl -- the MSR[WE] will take effect when the guest is next entered.

It also causes SRR1[WE] to be set when we enter the guest's interrupt
handler, which is what e500 hardware is documented to do.

Signed-off-by: Scott Wood <scottwood@freescale.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Avi Kivity <avi@redhat.com>
2012-03-05 14:52:26 +02:00
Scott Wood
25051b5a5a KVM: PPC: Move prepare_to_enter call site into subarch code
This function should be called with interrupts disabled, to avoid
a race where an exception is delivered after we check, but the
resched kick is received before we disable interrupts (and thus doesn't
actually trigger the exit code that would recheck exceptions).

booke already does this properly in the lightweight exit case, but
not on initial entry.

For now, move the call of prepare_to_enter into subarch-specific code so
that booke can do the right thing here.  Ideally book3s would do the same
thing, but I'm having a hard time seeing where it does any interrupt
disabling of this sort (plus it has several additional call sites), so
I'm deferring the book3s fix to someone more familiar with that code.
book3s behavior should be unchanged by this patch.

Signed-off-by: Scott Wood <scottwood@freescale.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Avi Kivity <avi@redhat.com>
2012-03-05 14:52:26 +02:00
Scott Wood
7e28e60ef9 KVM: PPC: Rename deliver_interrupts to prepare_to_enter
This function also updates paravirt int_pending, so rename it
to be more obvious that this is a collection of checks run prior
to (re)entering a guest.

Signed-off-by: Scott Wood <scottwood@freescale.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Avi Kivity <avi@redhat.com>
2012-03-05 14:52:25 +02:00
Scott Wood
1d1ef22208 KVM: PPC: booke: check for signals in kvmppc_vcpu_run
Currently we check prior to returning from a lightweight exit,
but not prior to initial entry.

book3s already does a similar test.

Signed-off-by: Scott Wood <scottwood@freescale.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Avi Kivity <avi@redhat.com>
2012-03-05 14:52:25 +02:00
Bharat Bhushan
7401f6266d KVM: PPC: booke: Do Not start decrementer when SPRN_DEC set 0
As per specification the decrementer interrupt not happen when DEC is written
with 0. Also when DEC is zero, no decrementer running. So we should not start
hrtimer for decrementer when DEC = 0.

Signed-off-by: Bharat Bhushan <bharat.bhushan@freescale.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Avi Kivity <avi@redhat.com>
2012-03-05 14:52:25 +02:00
Bharat Bhushan
dc2babfea5 KVM: PPC: Fix DEC truncation for greater than 0xffff_ffff/1000
kvmppc_emulate_dec() uses dec_nsec of type unsigned long and does below calculation:

        dec_nsec = vcpu->arch.dec;
        dec_nsec *= 1000;
This will truncate if DEC value "vcpu->arch.dec" is greater than 0xffff_ffff/1000.
For example : For tb_ticks_per_usec = 4a, we can not set decrementer more than ~58ms.

Signed-off-by: Bharat Bhushan <bharat.bhushan@freescale.com>
Acked-by: Liu Yu <yu.liu@freescale.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Avi Kivity <avi@redhat.com>
2012-03-05 14:52:25 +02:00
Bharat Bhushan
f9208427f7 PPC: Fix race in mtmsr paravirt implementation
The current implementation of mtmsr and mtmsrd are racy in that it does:

  * check (int_pending == 0)
  ---> host sets int_pending = 1 <---
  * write shared page
  * done

while instead we should check for int_pending after the shared page is written.

Signed-off-by: Bharat Bhushan <bharat.bhushan@freescale.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Avi Kivity <avi@redhat.com>
2012-03-05 14:52:24 +02:00
Alexander Graf
95325e6b19 KVM: PPC: E500: Support hugetlbfs
With hugetlbfs support emerging on e500, we should also support KVM
backing its guest memory by it.

This patch adds support for hugetlbfs into the e500 shadow mmu code.

Signed-off-by: Alexander Graf <agraf@suse.de>
Acked-by: Scott Wood <scottwood@freescale.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2012-03-05 14:52:24 +02:00
Scott Wood
841741f23b KVM: PPC: e500: Don't hardcode PIR=0
The hardcoded behavior prevents proper SMP support.

user space shall specify the vcpu's PIR as the vcpu id.

Signed-off-by: Scott Wood <scottwood@freescale.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Avi Kivity <avi@redhat.com>
2012-03-05 14:52:24 +02:00
Scott Wood
303b7c97e3 KVM: PPC: e500: tlbsx: fix tlb0 esel
It should contain the way, not the absolute TLB0 index.

Signed-off-by: Scott Wood <scottwood@freescale.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Avi Kivity <avi@redhat.com>
2012-03-05 14:52:24 +02:00
Scott Wood
dc83b8bc02 KVM: PPC: e500: MMU API
This implements a shared-memory API for giving host userspace access to
the guest's TLB.

Signed-off-by: Scott Wood <scottwood@freescale.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Avi Kivity <avi@redhat.com>
2012-03-05 14:52:24 +02:00