The hash mmu page fault handling code is responsible for generating ISIs
and DSIs when access permissions cause an access to fail. Part of this
involves setting the srr1 or dsisr registers to indicate what causes the
access to fail. Add defines for the bit fields of these registers and
rework the code to use these new defines in order to improve readability
and code clarity.
While we're here, update what is logged when an access fails to include
information as to what caused to access to fail for debug purposes.
Signed-off-by: Suraj Jitindar Singh <sjitindarsingh@gmail.com>
[dwg: Moved constants to cpu.h since they're not MMUv3 specific]
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
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>
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>
ISA v3.00 adds the idea of a partition table which is used to store the
address translation details for all partitions on the system. The partition
table consists of double word entries indexed by partition id where the second
double word contains the location of the process table in guest memory. The
process table is registered by the guest via a h-call.
We need somewhere to store the address of the process table so we add an entry
to the sPAPRMachineState struct called patb_entry to represent the second
doubleword of a single partition table entry corresponding to the current
guest. We need to store this value so we know if the guest is using radix or
hash translation and the location of the corresponding process table in guest
memory. Since we only have a single guest per qemu instance, we only need one
entry.
Since the partition table is technically a hypervisor resource we require that
access to it is abstracted by the virtual hypervisor through the get_patbe()
call. Currently the value of the entry is never set (and thus
defaults to 0 indicating hash), but it will be required to both implement
POWER9 kvm support and tcg radix support.
We also add this field to be migrated as part of the sPAPRMachineState as we
will need it on the receiving side as the guest will never tell us this
information again and we need it to perform translation.
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>
This patch extends support for the `dump-guest-memory` command to the
32-bit PowerPC architecture. It relies on the assumption that a 64-bit
guest will not dump a 32-bit core file (and vice versa).
[dwg: I suspect this patch won't cover all cases, in particular a
32-bit machine type on a 64-bit qemu build. However, it does strictly
more than what we had before, so might as well apply as a starting
point]
Signed-off-by: Mike Nawrocki <michael.nawrocki@gtri.gatech.edu>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
POWER ISA 3.0 adds CA32 and OV32 status in 64-bit mode. Add the flags
and corresponding defines.
Moreover, CA32 is updated when CA is updated and OV32 is updated when OV
is updated.
Arithmetic instructions:
* Addition and Substractions:
addic, addic., subfic, addc, subfc, adde, subfe, addme, subfme,
addze, and subfze always updates CA and CA32.
=> CA reflects the carry out of bit 0 in 64-bit mode and out of
bit 32 in 32-bit mode.
=> CA32 reflects the carry out of bit 32 independent of the
mode.
=> SO and OV reflects overflow of the 64-bit result in 64-bit
mode and overflow of the low-order 32-bit result in 32-bit
mode
=> OV32 reflects overflow of the low-order 32-bit independent of
the mode
* Multiply Low and Divide:
For mulld, divd, divde, divdu and divdeu: SO, OV, and OV32 bits
reflects overflow of the 64-bit result
For mullw, divw, divwe, divwu and divweu: SO, OV, and OV32 bits
reflects overflow of the 32-bit result
* Negate with OE=1 (nego)
For 64-bit mode if the register RA contains
0x8000_0000_0000_0000, OV and OV32 are set to 1.
For 32-bit mode if the register RA contains 0x8000_0000, OV and
OV32 are set to 1.
Signed-off-by: Nikunj A Dadhania <nikunj@linux.vnet.ibm.com>
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>
cpu_ppc_set_papr() sets up various aspects of CPU state for use with PAPR
paravirtualized guests. However, it doesn't set the virtual hypervisor,
so callers must also call cpu_ppc_set_vhyp() so that PAPR hypercalls are
handled properly. This is a bit silly, so fold setting the virtual
hypervisor into cpu_ppc_set_papr().
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Reviewed-by: Suraj Jitindar Singh <sjitindarsingh@gmail.com>
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>
Signed-off-by: Nikunj A Dadhania <nikunj@linux.vnet.ibm.com>
Reviewed-by: Richard Henderson <rth@twiddle.net>
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>
The DPFD field in the LPCR is 3 bits wide. This has always been defined
as 0x3 << shift which indicates a 2 bit field, which is incorrect.
Correct this.
Signed-off-by: Suraj Jitindar Singh <sjitindarsingh@gmail.com>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
pcr_supported is used to define the supported PCR values for a given
processor. A POWER9 processor can support 3.00, 2.07, 2.06 and 2.05
compatibility modes, thus we set this accordingly.
Signed-off-by: Suraj Jitindar Singh <sjitindarsingh@gmail.com>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Once a compatiblity mode is negotiated with the guest,
h_client_architecture_support() uses run_on_cpu() to update each CPU to
the new mode. We're going to want this logic somewhere else shortly,
so make a helper function to do this global update.
We put it in target-ppc/compat.c - it makes as much sense at the CPU level
as it does at the machine level. We also move the cpu_synchronize_state()
into ppc_set_compat(), since it doesn't really make any sense to call that
without synchronizing state.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Current ppc_set_compat() will attempt to set any compatiblity mode
specified, regardless of whether it's available on the CPU. The caller is
expected to make sure it is setting a possible mode, which is awkwward
because most of the information to make that decision is at the CPU level.
This begins to clean this up by introducing a ppc_check_compat() function
which will determine if a given compatiblity mode is supported on a CPU
(and also whether it lies within specified minimum and maximum compat
levels, which will be useful later). It also contains an assertion that
the CPU has a "virtual hypervisor"[1], that is, that the guest isn't
permitted to execute hypervisor privilege code. Without that, the guest
would own the PCR and so could override any mode set here. Only machine
types which use a virtual hypervisor (i.e. 'pseries') should use
ppc_check_compat().
ppc_set_compat() is modified to validate the compatibility mode it is given
and fail if it's not available on this CPU.
[1] Or user-only mode, which also obviously doesn't allow access to the
hypervisor privileged PCR. We don't use that now, but could in future.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Reviewed-by: Alexey Kardashevskiy <aik@ozlabs.ru>
To continue consolidation of compatibility mode information, this rewrites
the ppc_get_compat_smt_threads() function using the table of compatiblity
modes in target-ppc/compat.c.
It's not a direct replacement, the new ppc_compat_max_threads() function
has simpler semantics - it just returns the number of threads the cpu
model has, taking into account any compatiblity mode it is in.
This no longer takes into account kvmppc_smt_threads() as the previous
version did. That check wasn't useful because we check in
ppc_cpu_realizefn() that CPUs aren't instantiated with more threads
than kvm allows (or if we didn't things will already be broken and
this won't make it any worse).
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Reviewed-by: Alexey Kardashevskiy <aik@ozlabs.ru>
This rewrites the ppc_set_compat() function so that instead of open coding
the various compatibility modes, it reads the relevant data from a table.
This is a first step in consolidating the information on compatibility
modes scattered across the code into a single place.
It also makes one change to the logic. The old code masked the bits
to be set in the PCR (Processor Compatibility Register) by which bits
are valid on the host CPU. This made no sense, since it was done
regardless of whether our guest CPU was the same as the host CPU or
not. Furthermore, the actual PCR bits are only relevant for TCG[1] -
KVM instead uses the compatibility mode we tell it in
kvmppc_set_compat(). When using TCG host cpu information usually
isn't even present.
While we're at it, we put the new implementation in a new file to make the
enormous translate_init.c a little smaller.
[1] Actually it doesn't even do anything in TCG, but it will if / when we
get to implementing compatibility mode logic at that level.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Reviewed-by: Alexey Kardashevskiy <aik@ozlabs.ru>
The 'cpu_version' field in PowerPCCPU is badly named. It's named after the
'cpu-version' device tree property where it is advertised, but that meaning
may not be obvious in most places it appears.
Worse, it doesn't even really correspond to that device tree property. The
property contains either the processor's PVR, or, if the CPU is running in
a compatibility mode, a special "logical PVR" representing which mode.
Rename the cpu_version field, and a number of related variables to
compat_pvr to make this clearer.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Reviewed-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Reviewed-by: Thomas Huth <thuth@redhat.com>
The pseries machine type is a bit unusual in that it runs a paravirtualized
guest. The guest expects to interact with a hypervisor, and qemu
emulates the functions of that hypervisor directly, rather than executing
hypervisor code within the emulated system.
To implement this in TCG, we need to intercept hypercall instructions and
direct them to the machine's hypercall handlers, rather than attempting to
perform a privilege change within TCG. This is controlled by a global
hook - cpu_ppc_hypercall.
This cleanup makes the handling a little cleaner and more extensible than
a single global variable. Instead, each CPU to have hypercalls intercepted
has a pointer set to a QOM object implementing a new virtual hypervisor
interface. A method in that interface is called by TCG when it sees a
hypercall instruction. It's possible we may want to add other methods in
future.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Reviewed-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Add _BIT to CRF_[GT,LT,EQ_SO] and introduce CRF_[GT,LT,EQ,SO] for usage
without shifts in the code. This would simplify the code.
Signed-off-by: Nikunj A Dadhania <nikunj@linux.vnet.ibm.com>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
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>
