Both KVM_CREATE_SPAPR_TCE_64 and KVM_REINJECT_CONTROL have section number
4.98 in Documentation/virtual/kvm/api.txt, presumably due to a naive merge.
This corrects the duplication.
[paulus@ozlabs.org - correct section numbers for following sections,
KVM_PPC_CONFIGURE_V3_MMU and KVM_PPC_GET_RMMU_INFO, as well.]
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
This merges in the POWER9 radix MMU host and guest support, which
was put into a topic branch because it touches both powerpc and
KVM code.
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
This adds a few last pieces of the support for radix guests:
* Implement the backends for the KVM_PPC_CONFIGURE_V3_MMU and
KVM_PPC_GET_RMMU_INFO ioctls for radix guests
* On POWER9, allow secondary threads to be on/off-lined while guests
are running.
* Set up LPCR and the partition table entry for radix guests.
* Don't allocate the rmap array in the kvm_memory_slot structure
on radix.
* Don't try to initialize the HPT for radix guests, since they don't
have an HPT.
* Take out the code that prevents the HV KVM module from
initializing on radix hosts.
At this stage, we only support radix guests if the host is running
in radix mode, and only support HPT guests if the host is running in
HPT mode. Thus a guest cannot switch from one mode to the other,
which enables some simplifications.
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
On POWER9 DD1, we need to invalidate the ERAT (effective to real
address translation cache) when changing the PIDR register, which
we do as part of guest entry and exit.
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
If we allow LPCR[AIL] to be set for radix guests, then interrupts from
the guest to the host can be delivered by the hardware with relocation
on, and thus the code path starting at kvmppc_interrupt_hv can be
executed in virtual mode (MMU on) for radix guests (previously it was
only ever executed in real mode).
Most of the code is indifferent to whether the MMU is on or off, but
the calls to OPAL that use the real-mode OPAL entry code need to
be switched to use the virtual-mode code instead. The affected
calls are the calls to the OPAL XICS emulation functions in
kvmppc_read_one_intr() and related functions. We test the MSR[IR]
bit to detect whether we are in real or virtual mode, and call the
opal_rm_* or opal_* function as appropriate.
The other place that depends on the MMU being off is the optimization
where the guest exit code jumps to the external interrupt vector or
hypervisor doorbell interrupt vector, or returns to its caller (which
is __kvmppc_vcore_entry). If the MMU is on and we are returning to
the caller, then we don't need to use an rfid instruction since the
MMU is already on; a simple blr suffices. If there is an external
or hypervisor doorbell interrupt to handle, we branch to the
relocation-on version of the interrupt vector.
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
With radix, the guest can do TLB invalidations itself using the tlbie
(global) and tlbiel (local) TLB invalidation instructions. Linux guests
use local TLB invalidations for translations that have only ever been
accessed on one vcpu. However, that doesn't mean that the translations
have only been accessed on one physical cpu (pcpu) since vcpus can move
around from one pcpu to another. Thus a tlbiel might leave behind stale
TLB entries on a pcpu where the vcpu previously ran, and if that task
then moves back to that previous pcpu, it could see those stale TLB
entries and thus access memory incorrectly. The usual symptom of this
is random segfaults in userspace programs in the guest.
To cope with this, we detect when a vcpu is about to start executing on
a thread in a core that is a different core from the last time it
executed. If that is the case, then we mark the core as needing a
TLB flush and then send an interrupt to any thread in the core that is
currently running a vcpu from the same guest. This will get those vcpus
out of the guest, and the first one to re-enter the guest will do the
TLB flush. The reason for interrupting the vcpus executing on the old
core is to cope with the following scenario:
CPU 0 CPU 1 CPU 4
(core 0) (core 0) (core 1)
VCPU 0 runs task X VCPU 1 runs
core 0 TLB gets
entries from task X
VCPU 0 moves to CPU 4
VCPU 0 runs task X
Unmap pages of task X
tlbiel
(still VCPU 1) task X moves to VCPU 1
task X runs
task X sees stale TLB
entries
That is, as soon as the VCPU starts executing on the new core, it
could unmap and tlbiel some page table entries, and then the task
could migrate to one of the VCPUs running on the old core and
potentially see stale TLB entries.
Since the TLB is shared between all the threads in a core, we only
use the bit of kvm->arch.need_tlb_flush corresponding to the first
thread in the core. To ensure that we don't have a window where we
can miss a flush, this moves the clearing of the bit from before the
actual flush to after it. This way, two threads might both do the
flush, but we prevent the situation where one thread can enter the
guest before the flush is finished.
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
If the guest is in radix mode, then it doesn't have a hashed page
table (HPT), so all of the hypercalls that manipulate the HPT can't
work and should return an error. This adds checks to make them
return H_FUNCTION ("function not supported").
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
This adds code to keep track of dirty pages when requested (that is,
when memslot->dirty_bitmap is non-NULL) for radix guests. We use the
dirty bits in the PTEs in the second-level (partition-scoped) page
tables, together with a bitmap of pages that were dirty when their
PTE was invalidated (e.g., when the page was paged out). This bitmap
is stored in the first half of the memslot->dirty_bitmap area, and
kvm_vm_ioctl_get_dirty_log_hv() now uses the second half for the
bitmap that gets returned to userspace.
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
This adapts our implementations of the MMU notifier callbacks
(unmap_hva, unmap_hva_range, age_hva, test_age_hva, set_spte_hva)
to call radix functions when the guest is using radix. These
implementations are much simpler than for HPT guests because we
have only one PTE to deal with, so we don't need to traverse
rmap chains.
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
This adds the code to construct the second-level ("partition-scoped" in
architecturese) page tables for guests using the radix MMU. Apart from
the PGD level, which is allocated when the guest is created, the rest
of the tree is all constructed in response to hypervisor page faults.
As well as hypervisor page faults for missing pages, we also get faults
for reference/change (RC) bits needing to be set, as well as various
other error conditions. For now, we only set the R or C bit in the
guest page table if the same bit is set in the host PTE for the
backing page.
This code can take advantage of the guest being backed with either
transparent or ordinary 2MB huge pages, and insert 2MB page entries
into the guest page tables. There is no support for 1GB huge pages
yet.
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
This adds code to branch around the parts that radix guests don't
need - clearing and loading the SLB with the guest SLB contents,
saving the guest SLB contents on exit, and restoring the host SLB
contents.
Since the host is now using radix, we need to save and restore the
host value for the PID register.
On hypervisor data/instruction storage interrupts, we don't do the
guest HPT lookup on radix, but just save the guest physical address
for the fault (from the ASDR register) in the vcpu struct.
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
This adds a field in struct kvm_arch and an inline helper to
indicate whether a guest is a radix guest or not, plus a new file
to contain the radix MMU code, which currently contains just a
translate function which knows how to traverse the guest page
tables to translate an address.
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
POWER9 adds a register called ASDR (Access Segment Descriptor
Register), which is set by hypervisor data/instruction storage
interrupts to contain the segment descriptor for the address
being accessed, assuming the guest is using HPT translation.
(For radix guests, it contains the guest real address of the
access.)
Thus, for HPT guests on POWER9, we can use this register rather
than looking up the SLB with the slbfee. instruction.
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
This adds the implementation of the KVM_PPC_CONFIGURE_V3_MMU ioctl
for HPT guests on POWER9. With this, we can return 1 for the
KVM_CAP_PPC_MMU_HASH_V3 capability.
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
This adds two capabilities and two ioctls to allow userspace to
find out about and configure the POWER9 MMU in a guest. The two
capabilities tell userspace whether KVM can support a guest using
the radix MMU, or using the hashed page table (HPT) MMU with a
process table and segment tables. (Note that the MMUs in the
POWER9 processor cores do not use the process and segment tables
when in HPT mode, but the nest MMU does).
The KVM_PPC_CONFIGURE_V3_MMU ioctl allows userspace to specify
whether a guest will use the radix MMU or the HPT MMU, and to
specify the size and location (in guest space) of the process
table.
The KVM_PPC_GET_RMMU_INFO ioctl gives userspace information about
the radix MMU. It returns a list of supported radix tree geometries
(base page size and number of bits indexed at each level of the
radix tree) and the encoding used to specify the various page
sizes for the TLB invalidate entry instruction.
Initially, both capabilities return 0 and the ioctls return -EINVAL,
until the necessary infrastructure for them to operate correctly
is added.
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
With host and guest both using radix translation, it is feasible
for the host to take interrupts that come from the guest with
relocation on, and that is in fact what the POWER9 hardware will
do when LPCR[AIL] = 3. All such interrupts use HSRR0/1 not SRR0/1
except for system call with LEV=1 (hcall).
Therefore this adds the KVM tests to the _HV variants of the
relocation-on interrupt handlers, and adds the KVM test to the
relocation-on system call entry point.
We also instantiate the relocation-on versions of the hypervisor
data storage and instruction interrupt handlers, since these can
occur with relocation on in radix guests.
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
When changing a partition table entry on POWER9, we do a particular
form of the tlbie instruction which flushes all TLBs and caches of
the partition table for a given logical partition ID (LPID).
This instruction has a field in the instruction word, labelled R
(radix), which should be 1 if the partition was previously a radix
partition and 0 if it was a HPT partition. This implements that
logic.
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
This exports the pgtable_cache array and the pgtable_cache_add
function so that HV KVM can use them for allocating radix page
tables for guests.
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
This adds definitions for bits in the DSISR register which are used
by POWER9 for various translation-related exception conditions, and
for some more bits in the partition table entry that will be needed
by KVM.
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
To use radix as a guest, we first need to tell the hypervisor via
the ibm,client-architecture call first that we support POWER9 and
architecture v3.00, and that we can do either radix or hash and
that we would like to choose later using an hcall (the
H_REGISTER_PROC_TBL hcall).
Then we need to check whether the hypervisor agreed to us using
radix. We need to do this very early on in the kernel boot process
before any of the MMU initialization is done. If the hypervisor
doesn't agree, we can't use radix and therefore clear the radix
MMU feature bit.
Later, when we have set up our process table, which points to the
radix tree for each process, we need to install that using the
H_REGISTER_PROC_TBL hcall.
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
This fixes the byte index values for some of the option bits in
the "ibm,architectur-vec-5" property. The "platform facilities options"
bits are in byte 17 not byte 14, so the upper 8 bits of their
definitions need to be 0x11 not 0x0E. The "sub processor support" option
is in byte 21 not byte 15.
Note none of these options are actually looked up in
"ibm,architecture-vec-5" at this time, so there is no bug.
When checking whether option bits are set, we should check that
the offset of the byte being checked is less than the vector
length that we got from the hypervisor.
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Currently, if the kernel is running on a POWER9 processor under a
hypervisor, it will try to use the radix MMU even though it doesn't have
the necessary code to use radix under a hypervisor (it doesn't negotiate
use of radix, and it doesn't do the H_REGISTER_PROC_TBL hcall). The
result is that the guest kernel will crash when it tries to turn on the
MMU.
This fixes it by looking for the /chosen/ibm,architecture-vec-5
property, and if it exists, clears the radix MMU feature bit, before we
decide whether to initialize for radix or HPT. This property is created
by the hypervisor as a result of the guest calling the
ibm,client-architecture-support method to indicate its capabilities, so
it will indicate whether the hypervisor agreed to us using radix.
Systems without a hypervisor may have this property also (for example,
skiboot creates it), so we check the HV bit in the MSR to see whether we
are running as a guest or not. If we are in hypervisor mode, then we can
do whatever we like including using the radix MMU.
The reason for using this property is that in future, when we have
support for using radix under a hypervisor, we will need to check this
property to see whether the hypervisor agreed to us using radix.
Fixes: 2bfd65e45e ("powerpc/mm/radix: Add radix callbacks for early init routines")
Cc: stable@vger.kernel.org # v4.7+
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
64-bit Book3S exception handlers must find the dynamic kernel base
to add to the target address when branching beyond __end_interrupts,
in order to support kernel running at non-0 physical address.
Support this in KVM by branching with CTR, similarly to regular
interrupt handlers. The guest CTR saved in HSTATE_SCRATCH1 and
restored after the branch.
Without this, the host kernel hangs and crashes randomly when it is
running at a non-0 address and a KVM guest is started.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Acked-by: Paul Mackerras <paulus@ozlabs.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
The function kvmppc_handle_exit_pr() is quite huge and thus hard to read,
and even contains a "spaghetti-code"-like goto between the different case
labels of the big switch statement. This can be made much more readable
by moving the code related to injecting program interrupts / instruction
emulation into a separate function instead.
Signed-off-by: Thomas Huth <thuth@redhat.com>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
The H_PROD hypercall is supposed to wake up an idle vcpu. We have
an implementation, but because Linux doesn't use it except when
doing cpu hotplug, it was never tested properly. AIX does use it,
and reported it broken. It turns out we were waking the wrong
vcpu (the one doing H_PROD, not the target of the prod) and we
weren't handling the case where the target needs an IPI to wake
it. Fix it by using the existing kvmppc_fast_vcpu_kick_hv()
function, which is intended for this kind of thing, and by using
the target vcpu not the current vcpu.
We were also not looking at the prodded flag when checking whether a
ceded vcpu should wake up, so this adds checks for the prodded flag
alongside the checks for pending exceptions.
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
David Gibson
Paul Mackerras
Nicholas Piggin
Thomas Huth