A pte entry has bit fields which can be used to make a page no-execute or
guarded, if either of these bits are set then an instruction access to this
page will fail. Currently these bits are checked with the pp_prot function
however the ISA specifies that the access authority controlled by the
key-pp value pair should only be checked on an instruction access after
the no-execute and guard bits have already been verified to permit the
access.
Move the no-execute and guard bit checking into a new separate function.
Note that we can remove the check for the no-execute bit in the slb entry
since this check was already performed above when we obtained the slb
entry.
In the event that the no-execute or guard bits are set, an ISI should be
generated with the SRR1_NOEXEC_GUARD (0x10000000) bit set in srr1. Add a
define for this for clarity.
Signed-off-by: Suraj Jitindar Singh <sjitindarsingh@gmail.com>
[dwg: Move constants to cpu.h since they're not MMUv3 specific]
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Basic storage protection defines various access authority permissions
based on a slb storage key and pte pp value pair. This access authority
defines read, write and execute permissions however currently we only
use this to control read and write permissions and ignore the execute
control.
Fix the code to allow execute permissions based on the key-pp value pair.
Execute is allowed under the same conditions which enable reads.
(i.e. read permission -> execute permission)
Signed-off-by: Suraj Jitindar Singh <sjitindarsingh@gmail.com>
Acked-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
The instruction authority mask register (IAMR) can be used to restrict
permissions for instruction fetch accesses on a per key basis for each
of 32 different key values. Access permissions are derived based on the
specific key value stored in the relevant page table entry.
The IAMR was introduced in, and is present in processors since, POWER8
(ISA v2.07). Thus introduce a function to check access permissions based
on the pte key value and the contents of the IAMR when handling a page
fault to ensure sufficient access permissions for an instruction fetch.
A hash pte contains a key value in bits 2:3|52:54 of the second double word
of the pte, this key value gives an index into the IAMR which contains 32
2-bit access masks. If the least significant bit of the 2-bit access mask
corresponding to the given key value is set (IAMR[key] & 0x1 == 0x1) then
the instruction fetch is not permitted and an ISI is generated accordingly.
While we're here, add defines for the srr1 bits to be set for the ISI for
clarity.
e.g.
pte:
dw0 [XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX]
dw1 [XX01XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX010XXXXXXXXX]
^^ ^^^
key = 01010 (0x0a)
IAMR: [XXXXXXXXXXXXXXXXXXXX01XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX]
^^
Access mask = 0b01
Test access mask: 0b01 & 0x1 == 0x1
Least significant bit of the access mask is set, thus the instruction fetch
is not permitted. We should generate an instruction storage interrupt (ISI)
with bit 42 of SRR1 set to indicate access precluded by virtual page class
key protection.
Signed-off-by: Suraj Jitindar Singh <sjitindarsingh@gmail.com>
[dwg: Move new constants to cpu.h, since they're not MMUv3 specific]
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Add a new mmu fault handler for the POWER9 cpu and add it as the handler
for the POWER9 cpu definition.
This handler checks if the guest is radix or hash based on the value in the
partition table entry and calls the correct fault handler accordingly.
The hash fault handling code has also been updated to check if the
partition is using segment tables.
Currently only legacy hash (no segment tables) is supported.
Signed-off-by: Suraj Jitindar Singh <sjitindarsingh@gmail.com>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
The function ppc_hash64_set_sdr1 basically checked the htabsize and set an
error if it was too big, otherwise it just stored the value in SPR_SDR1.
Given that the only function which calls ppc_hash64_set_sdr1() is
ppc_store_sdr1(), why not handle the checking in ppc_store_sdr1() to avoid
the extra function call. Note that ppc_store_sdr1() already stores the
value in SPR_SDR1 anyway, so we were doing it twice.
Signed-off-by: Suraj Jitindar Singh <sjitindarsingh@gmail.com>
[dwg: Remove unnecessary error temporary]
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
The pseries machine type implements the behaviour of a PAPR compliant
hypervisor, without actually executing such a hypervisor on the virtual
CPU. To do this we need some hooks in the CPU code to make hypervisor
facilities get redirected to the machine instead of emulated internally.
For hypercalls this is managed through the cpu->vhyp field, which points
to a QOM interface with a method implementing the hypercall.
For the hashed page table (HPT) - also a hypervisor resource - we use an
older hack. CPUPPCState has an 'external_htab' field which when non-NULL
indicates that the HPT is stored in qemu memory, rather than within the
guest's address space.
For consistency - and to make some future extensions easier - this merges
the external HPT mechanism into the vhyp mechanism. Methods are added
to vhyp for the basic operations the core hash MMU code needs: map_hptes()
and unmap_hptes() for reading the HPT, store_hpte() for updating it and
hpt_mask() to retrieve its size.
To match this, the pseries machine now sets these vhyp fields in its
existing vhyp class, rather than reaching into the cpu object to set the
external_htab field.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Reviewed-by: Suraj Jitindar Singh <sjitindarsingh@gmail.com>
CPUPPCState includes fields htab_base and htab_mask which store the base
address (GPA) and size (as a mask) of the guest's hashed page table (HPT).
These are set when the SDR1 register is updated.
Keeping these in sync with the SDR1 is actually a little bit fiddly, and
probably not useful for performance, since keeping them expands the size of
CPUPPCState. It also makes some upcoming changes harder to implement.
This patch removes these fields, in favour of calculating them directly
from the SDR1 contents when necessary.
This does make a change to the behaviour of attempting to write a bad value
(invalid HPT size) to the SDR1 with an mtspr instruction. Previously, the
bad value would be stored in SDR1 and could be retrieved with a later
mfspr, but the HPT size as used by the softmmu would be, clamped to the
allowed values. Now, writing a bad value is treated as a no-op. An error
message is printed in both new and old versions.
I'm not sure which behaviour, if either, matches real hardware. I don't
think it matters that much, since it's pretty clear that if an OS writes
a bad value to SDR1, it's not going to boot.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Reviewed-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Accesses to the hashed page table (HPT) are complicated by the fact that
the HPT could be in one of three places:
1) Within guest memory - when we're emulating a full guest CPU at the
hardware level (e.g. powernv, mac99, g3beige)
2) Within qemu, but outside guest memory - when we're emulating user and
supervisor instructions within TCG, but instead of emulating
the CPU's hypervisor mode, we just emulate a hypervisor's behaviour
(pseries in TCG or KVM-PR)
3) Within the host kernel - a pseries machine using KVM-HV
acceleration. Mostly accesses to the HPT are handled by KVM,
but there are a few cases where qemu needs to access it via a
special fd for the purpose.
In order to batch accesses to the fd in case (3), we use a somewhat awkward
ppc_hash64_start_access() / ppc_hash64_stop_access() pair, which for case
(3) reads / releases several HPTEs from the kernel as a batch (usually a
whole PTEG). For cases (1) & (2) it just returns an address value. The
actual HPTE load helpers then need to interpret the returned token
differently in the 3 cases.
This patch keeps the same basic structure, but simplfiies the details.
First start_access() / stop_access() are renamed to map_hptes() and
unmap_hptes() to make their operation more obvious. Second, map_hptes()
now always returns a qemu pointer, which can always be used in the same way
by the load_hpte() helpers. In case (1) it comes from address_space_map()
in case (2) directly from qemu's HPT buffer and in case (3) from a
temporary buffer read from the KVM fd.
While we're at it, make things a bit more consistent in terms of types and
variable names: avoid variables named 'index' (it shadows index(3) which
can lead to confusing results), use 'hwaddr ptex' for HPTE indices and
uint64_t for each of the HPTE words, use ptex throughout the call stack
instead of pte_offset in some places (we still need that at the bottom
layer, but nowhere else).
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
When a 'pseries' guest is running with KVM-HV, the guest's hashed page
table (HPT) is stored within the host kernel, so it is not directly
accessible to qemu. Most of the time, qemu doesn't need to access it:
we're using the hardware MMU, and KVM itself implements the guest
hypercalls for manipulating the HPT.
However, qemu does need access to the in-KVM HPT to implement
get_phys_page_debug() for the benefit of the gdbstub, and maybe for
other debug operations.
To allow this, 7c43bca "target-ppc: Fix page table lookup with kvm
enabled" added kvmppc_hash64_read_pteg() to target/ppc/kvm.c to read
in a batch of HPTEs from the KVM table. Unfortunately, there are a
couple of problems with this:
First, the name of the function implies it always reads a whole PTEG
from the HPT, but in fact in some cases it's used to grab individual
HPTEs (which ends up pulling 8 HPTEs, not aligned to a PTEG from the
kernel).
Second, and more importantly, the code to read the HPTEs from KVM is
simply wrong, in general. The data from the fd that KVM provides is
designed mostly for compact migration rather than this sort of one-off
access, and so needs some decoding for this purpose. The current code
will work in some cases, but if there are invalid HPTEs then it will
not get sane results.
This patch rewrite the HPTE reading function to have a simpler
interface (just read n HPTEs into a caller provided buffer), and to
correctly decode the stream from the kernel.
For consistency we also clean up the similar function for altering
HPTEs within KVM (introduced in c138593 "target-ppc: Update
ppc_hash64_store_hpte to support updating in-kernel htab").
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
The vpm0 bit was removed from the LPCR in POWER9, this bit controlled
whether ISI and DSI interrupts were directed to the hypervisor or the
partition. These interrupts now go to the hypervisor irrespective, thus
it is no longer necessary to check the vmp0 bit in the LPCR.
Signed-off-by: Suraj Jitindar Singh <sjitindarsingh@gmail.com>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
The logical partitioning control register controls a threads operation
based on the partition it is currently executing. Add new definitions and
update the mask used when writing to the LPCR based on the POWER9 spec.
Signed-off-by: Suraj Jitindar Singh <sjitindarsingh@gmail.com>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
slbieg: SLB Invalidate Entry Global
Signed-off-by: Nikunj A Dadhania <nikunj@linux.vnet.ibm.com>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
We were printing an unsigned value as a signed value, fix this.
Signed-off-by: Suraj Jitindar Singh <sjitindarsingh@gmail.com>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Move the generic cpu_synchronize_ functions to the common hw_accel.h header,
in order to prepare for the addition of a second hardware accelerator.
Signed-off-by: Stefan Weil <sw@weilnetz.de>
Signed-off-by: Vincent Palatin <vpalatin@chromium.org>
Message-Id: <f5c3cffe8d520011df1c2e5437bb814989b48332.1484045952.git.vpalatin@chromium.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
We've currently got 18 architectures in QEMU, and thus 18 target-xxx
folders in the root folder of the QEMU source tree. More architectures
(e.g. RISC-V, AVR) are likely to be included soon, too, so the main
folder of the QEMU sources slowly gets quite overcrowded with the
target-xxx folders.
To disburden the main folder a little bit, let's move the target-xxx
folders into a dedicated target/ folder, so that target-xxx/ simply
becomes target/xxx/ instead.
Acked-by: Laurent Vivier <laurent@vivier.eu> [m68k part]
Acked-by: Bastian Koppelmann <kbastian@mail.uni-paderborn.de> [tricore part]
Acked-by: Michael Walle <michael@walle.cc> [lm32 part]
Acked-by: Cornelia Huck <cornelia.huck@de.ibm.com> [s390x part]
Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com> [s390x part]
Acked-by: Eduardo Habkost <ehabkost@redhat.com> [i386 part]
Acked-by: Artyom Tarasenko <atar4qemu@gmail.com> [sparc part]
Acked-by: Richard Henderson <rth@twiddle.net> [alpha part]
Acked-by: Max Filippov <jcmvbkbc@gmail.com> [xtensa part]
Reviewed-by: David Gibson <david@gibson.dropbear.id.au> [ppc part]
Acked-by: Edgar E. Iglesias <edgar.iglesias@xilinx.com> [crisµblaze part]
Acked-by: Guan Xuetao <gxt@mprc.pku.edu.cn> [unicore32 part]
Signed-off-by: Thomas Huth <thuth@redhat.com>
