Avoid the use of the OptContext slots.
Reviewed-by: Pierrick Bouvier <pierrick.bouvier@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Avoid the use of the OptContext slots.
Reviewed-by: Pierrick Bouvier <pierrick.bouvier@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Avoid the use of the OptContext slots.
Reviewed-by: Pierrick Bouvier <pierrick.bouvier@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Change return from bool to int; distinguish between
complete folding, simplification, and no change.
Reviewed-by: Pierrick Bouvier <pierrick.bouvier@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Stores have no output operands, and so need no further work.
Reviewed-by: Pierrick Bouvier <pierrick.bouvier@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Avoid the use of the OptContext slots.
Be careful not to call fold_masks_zs when the memory operation
is wide enough to require multiple outputs, so split into two
functions: fold_qemu_ld_1reg and fold_qemu_ld_2reg.
Reviewed-by: Pierrick Bouvier <pierrick.bouvier@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Avoid the use of the OptContext slots.
Reviewed-by: Pierrick Bouvier <pierrick.bouvier@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Avoid the use of the OptContext slots. Find TempOptInfo once.
Reviewed-by: Pierrick Bouvier <pierrick.bouvier@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Avoid the use of the OptContext slots.
Reviewed-by: Pierrick Bouvier <pierrick.bouvier@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Avoid the use of the OptContext slots.
Reviewed-by: Pierrick Bouvier <pierrick.bouvier@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Avoid the use of the OptContext slots.
Reviewed-by: Pierrick Bouvier <pierrick.bouvier@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Avoid the use of the OptContext slots.
Reviewed-by: Pierrick Bouvier <pierrick.bouvier@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Avoid the use of the OptContext slots. Find TempOptInfo once.
Reviewed-by: Pierrick Bouvier <pierrick.bouvier@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Avoid the use of the OptContext slots.
Reviewed-by: Pierrick Bouvier <pierrick.bouvier@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Avoid the use of the OptContext slots. Find TempOptInfo once.
Explicitly sign-extend z_mask instead of doing that manually.
Reviewed-by: Pierrick Bouvier <pierrick.bouvier@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Avoid the use of the OptContext slots. Find TempOptInfo once.
Reviewed-by: Pierrick Bouvier <pierrick.bouvier@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Add fold_masks_s as a trivial wrapper around fold_masks_zs.
Avoid the use of the OptContext slots.
Reviewed-by: Pierrick Bouvier <pierrick.bouvier@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
The input which overlaps the sign bit of the output can
have its input s_mask propagated to the output s_mask.
Reviewed-by: Pierrick Bouvier <pierrick.bouvier@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Avoid the use of the OptContext slots. Find TempOptInfo once.
When we fold to and, use fold_and.
Reviewed-by: Pierrick Bouvier <pierrick.bouvier@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Add fold_masks_z as a trivial wrapper around fold_masks_zs.
Avoid the use of the OptContext slots.
Reviewed-by: Pierrick Bouvier <pierrick.bouvier@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Avoid the use of the OptContext slots. Find TempOptInfo once.
Compute s_mask from the union of the maximum count and the
op2 fallback for op1 being zero.
Reviewed-by: Pierrick Bouvier <pierrick.bouvier@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Avoid the use of the OptContext slots. Find TempOptInfo once.
Always set s_mask along the BSWAP_OS path, since the result is
being explicitly sign-extended.
Reviewed-by: Pierrick Bouvier <pierrick.bouvier@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Avoid the use of the OptContext slots. Find TempOptInfo once.
Avoid double inversion of the value of second const operand.
Reviewed-by: Pierrick Bouvier <pierrick.bouvier@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Avoid the use of the OptContext slots. Find TempOptInfo once.
Sink mask computation below fold_affected_mask early exit.
Reviewed-by: Pierrick Bouvier <pierrick.bouvier@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Change the representation from sign bit repetitions to all bits equal
to the sign bit, including the sign bit itself.
The previous format has a problem in that it is difficult to recreate
a valid sign mask after a shift operation: the "repetitions" part of
the previous format meant that applying the same shift as for the value
lead to an off-by-one value.
The new format, including the sign bit itself, means that the sign mask
can be manipulated in exactly the same way as the value, canonicalization
is easier.
Canonicalize the s_mask in fold_masks_zs, rather than requiring callers
to do so. Treat 0 as a non-canonical but typeless input for no sign
information, which will be reset as appropriate for the data type.
We can easily fold in the data from z_mask while canonicalizing.
Temporarily disable optimizations using s_mask while each operation is
converted to use fold_masks_zs and to the new form.
Reviewed-by: Pierrick Bouvier <pierrick.bouvier@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Consider the passed s_mask to be a minimum deduced from
either existing s_mask or from a sign-extension operation.
We may be able to deduce more from the set of known zeros.
Remove identical logic from several opcode folders.
Reviewed-by: Pierrick Bouvier <pierrick.bouvier@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Add a routine to which masks can be passed directly, rather than
storing them into OptContext. To be used in upcoming patches.
Reviewed-by: Pierrick Bouvier <pierrick.bouvier@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Use of fold_masks should be restricted to those opcodes that
can reliably make use of it -- those with a single output,
and from higher-level folders that set up the masks.
Prepare for conversion of each folder in turn.
Reviewed-by: Pierrick Bouvier <pierrick.bouvier@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
There are only a few logical operations which can compute
an "affected" mask. Split out handling of this optimization
to a separate function, only to be called when applicable.
Remove the a_mask field from OptContext, as the mask is
no longer stored anywhere.
Reviewed-by: Pierrick Bouvier <pierrick.bouvier@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Call them directly from the opcode switch statement in tcg_optimize,
rather than in finish_folding based on opcode flags. Adjust folding
of conditional branches to match.
Reviewed-by: Pierrick Bouvier <pierrick.bouvier@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
When running with a single vcpu, we can return a constant instead of a
load when accessing cpu_index.
A side effect is that all tcg operations using it are optimized, most
notably scoreboard access.
When running a simple loop in user-mode, the speedup is around 20%.
Signed-off-by: Pierrick Bouvier <pierrick.bouvier@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Message-ID: <20241128213843.1023080-1-pierrick.bouvier@linaro.org>
make check-tcg fails on Fedora with the following error message:
alpha-linux-gnu-gcc [...] qemu/tests/tcg/multiarch/system/memory.c -o memory [...]
qemu/tests/tcg/multiarch/system/memory.c:17:10: fatal error: inttypes.h: No such file or directory
17 | #include <inttypes.h>
| ^~~~~~~~~~~~
compilation terminated.
The reason is that Fedora has cross-compilers, but no cross-glibc
headers. Fix by hardcoding the format specifiers and dropping the
include.
An alternative fix would be to introduce a configure check for
inttypes.h. But this would make it impossible to use Fedora
cross-compilers for softmmu tests, which used to work so far.
Fixes: ecbcc9ead2 ("tests/tcg: add a system test to check memory instrumentation")
Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Message-ID: <20241010085906.226249-1-iii@linux.ibm.com>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
"Host Memory Backends" and "Memory devices" queue ("mem"):
- Fixup handling of virtio-mem unplug during system resets, as
preparation for s390x support (especially kdump in the Linux guest)
- virtio-mem support for s390x
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Merge tag 'mem-2024-12-21' of https://github.com/davidhildenbrand/qemu into staging
Hi,
"Host Memory Backends" and "Memory devices" queue ("mem"):
- Fixup handling of virtio-mem unplug during system resets, as
preparation for s390x support (especially kdump in the Linux guest)
- virtio-mem support for s390x
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# gpg: Signature made Sat 21 Dec 2024 14:17:18 EST
# gpg: using RSA key 1BD9CAAD735C4C3A460DFCCA4DDE10F700FF835A
# gpg: issuer "david@redhat.com"
# gpg: Good signature from "David Hildenbrand <david@redhat.com>" [unknown]
# gpg: aka "David Hildenbrand <davidhildenbrand@gmail.com>" [full]
# gpg: aka "David Hildenbrand <hildenbr@in.tum.de>" [unknown]
# gpg: WARNING: The key's User ID is not certified with a trusted signature!
# gpg: There is no indication that the signature belongs to the owner.
# Primary key fingerprint: 1BD9 CAAD 735C 4C3A 460D FCCA 4DDE 10F7 00FF 835A
* tag 'mem-2024-12-21' of https://github.com/davidhildenbrand/qemu:
s390x: virtio-mem support
s390x/virtio-ccw: add support for virtio based memory devices
s390x: remember the maximum page size
s390x/pv: prepare for memory devices
s390x/s390-virtio-ccw: prepare for memory devices
s390x/s390-skeys: prepare for memory devices
s390x/s390-stattrib-kvm: prepare for memory devices and sparse memory layouts
s390x/s390-hypercall: introduce DIAG500 STORAGE_LIMIT
s390x: introduce s390_get_memory_limit()
s390x/s390-virtio-ccw: move setting the maximum guest size from sclp to machine code
s390x: rename s390-virtio-hcall* to s390-hypercall*
s390x/s390-virtio-hcall: prepare for more diag500 hypercalls
s390x/s390-virtio-hcall: remove hypercall registration mechanism
s390x/s390-virtio-ccw: don't crash on weird RAM sizes
virtio-mem: unplug memory only during system resets, not device resets
Conflicts:
- hw/s390x/s390-stattrib-kvm.c
sysemu/ -> system/ header rename conflict.
- hw/s390x/virtio-ccw-mem.c
Make Property array const and removed DEFINE_PROP_END_OF_LIST() to
conform to the latest conventions.
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Let's add our virtio-mem-ccw proxy device and wire it up. We should
be supporting everything (e.g., device unplug, "dynamic-memslots") that
we already support for the virtio-pci variant.
With a Linux guest that supports virtio-mem (and has automatic memory
onlining properly configured) the following example will work:
1. Start a VM with 4G initial memory and a virtio-mem device with a maximum
capacity of 16GB:
qemu/build/qemu-system-s390x \
--enable-kvm \
-m 4G,maxmem=20G \
-nographic \
-smp 8 \
-hda Fedora-Server-KVM-40-1.14.s390x.qcow2 \
-chardev socket,id=monitor,path=/var/tmp/monitor,server,nowait \
-mon chardev=monitor,mode=readline \
-object memory-backend-ram,id=mem0,size=16G,reserve=off \
-device virtio-mem-ccw,id=vmem0,memdev=mem0,dynamic-memslots=on
2. Query the current size of virtio-mem device:
(qemu) info memory-devices
Memory device [virtio-mem]: "vmem0"
memaddr: 0x100000000
node: 0
requested-size: 0
size: 0
max-size: 17179869184
block-size: 1048576
memdev: /objects/mem0
3. Request to grow it to 8GB (hotplug 8GB):
(qemu) qom-set vmem0 requested-size 8G
(qemu) info memory-devices
Memory device [virtio-mem]: "vmem0"
memaddr: 0x100000000
node: 0
requested-size: 8589934592
size: 8589934592
max-size: 17179869184
block-size: 1048576
memdev: /objects/mem0
4. Request to grow to 16GB (hotplug another 8GB):
(qemu) qom-set vmem0 requested-size 16G
(qemu) info memory-devices
Memory device [virtio-mem]: "vmem0"
memaddr: 0x100000000
node: 0
requested-size: 17179869184
size: 17179869184
max-size: 17179869184
block-size: 1048576
memdev: /objects/mem0
5. Try to hotunplug all memory again, shrinking to 0GB:
(qemu) qom-set vmem0 requested-size 0G
(qemu) info memory-devices
Memory device [virtio-mem]: "vmem0"
memaddr: 0x100000000
node: 0
requested-size: 0
size: 0
max-size: 17179869184
block-size: 1048576
memdev: /objects/mem0
6. If it worked, unplug the device
(qemu) device_del vmem0
(qemu) info memory-devices
(qemu) object_del mem0
7. Hotplug a new device with a smaller capacity and directly size it to 1GB
(qemu) object_add memory-backend-ram,id=mem0,size=8G,reserve=off
(qemu) device_add virtio-mem-ccw,id=vmem0,memdev=mem0,\
dynamic-memslots=on,requested-size=1G
(qemu) info memory-devices
Memory device [virtio-mem]: "vmem0"
memaddr: 0x100000000
node: 0
requested-size: 1073741824
size: 1073741824
max-size: 8589934592
block-size: 1048576
memdev: /objects/mem0
Trying to use a virtio-mem device backed by hugetlb into a !hugetlb VM
correctly results in the error:
... Memory device uses a bigger page size than initial memory
Note that the virtio-mem driver in Linux will supports 1 MiB (pageblock)
granularity.
Message-ID: <20241219144115.2820241-15-david@redhat.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: David Hildenbrand <david@redhat.com>
Let's implement support for abstract virtio based memory devices, using
the virtio-pci implementation as an orientation. Wire them up in the
machine hotplug handler, taking care of s390x page size limitations.
As we neither support virtio-mem or virtio-pmem yet, the code is
effectively unused. We'll implement support for virtio-mem based on this
next.
Note that we won't wire up the virtio-pci variant (should currently be
impossible due to lack of support for MSI-X), but we'll add a safety net
to reject plugging them in the pre-plug handler.
Message-ID: <20241219144115.2820241-14-david@redhat.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: David Hildenbrand <david@redhat.com>
Let's remember the value (successfully) set via s390_set_max_pagesize().
This will be helpful to reject hotplugged memory devices that would exceed
this initially set page size.
Handle it just like how we handle s390_get_memory_limit(), storing it in
the machine, and moving the handling to machine code.
Message-ID: <20241219144115.2820241-13-david@redhat.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Signed-off-by: David Hildenbrand <david@redhat.com>
Let's avoid checking for the maxram_size, and instead rely on the memory
limit determined in s390_memory_init(), that might be larger than
maxram_size, for example due to alignment purposes.
This check now correctly mimics what the kernel will check in
kvm_s390_pv_set_aside(), whereby a VM <= 2 GiB VM would end up using
a segment type ASCE.
Message-ID: <20241219144115.2820241-12-david@redhat.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Nina Schoetterl-Glausch <nsg@linux.ibm.com>
Signed-off-by: David Hildenbrand <david@redhat.com>
Let's prepare our address space for memory devices if enabled via
"maxmem" and if we have CONFIG_MEM_DEVICE enabled at all. Note that
CONFIG_MEM_DEVICE will be selected automatically once we add support
for devices.
Just like on other architectures, the region container for memory devices
is placed directly above our initial memory. For now, we only align the
start address of the region up to 1 GiB, but we won't add any additional
space to the region for internal alignment purposes; this can be done in
the future if really required.
The RAM size returned via SCLP is not modified, as this only
covers initial RAM (and standby memory we don't implement) and not memory
devices; clarify that in the docs of read_SCP_info(). Existing OSes without
support for memory devices will keep working as is, even when memory
devices would be attached the VM.
Guest OSs which support memory devices, such as virtio-mem, will
consult diag500(), to find out the maximum possible pfn. Guest OSes that
don't support memory devices, don't have to be changed and will continue
relying on information provided by SCLP.
There are no remaining maxram_size users in s390x code, and the remaining
ram_size users only care about initial RAM:
* hw/s390x/ipl.c
* hw/s390x/s390-hypercall.c
* hw/s390x/sclp.c
* target/s390x/kvm/pv.c
Message-ID: <20241219144115.2820241-11-david@redhat.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Signed-off-by: David Hildenbrand <david@redhat.com>
With memory devices, we will have storage keys for memory that
exceeds the initial ram size.
The TODO already states that current handling is subopimal,
but we won't worry about improving that (TCG-only) thing for now.
Message-ID: <20241219144115.2820241-10-david@redhat.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Signed-off-by: David Hildenbrand <david@redhat.com>
With memory devices, we will have storage attributes for memory that
exceeds the initial ram size. Further, we can easily have memory holes,
for which there (currently) are no storage attributes.
In particular, with memory holes, KVM_S390_SET_CMMA_BITS will fail to set
some storage attributes.
So let's do it like we handle storage keys migration, relying on
guest_phys_blocks_append(). However, in contrast to storage key
migration, we will handle it on the migration destination.
This is a preparation for virtio-mem support. Note that ever since the
"early migration" feature was added (x-early-migration), the state
of device blocks (plugged/unplugged) is migrated early such that
guest_phys_blocks_append() will properly consider all currently plugged
memory blocks and skip any unplugged ones.
In the future, we should try getting rid of the large temporary buffer
and also not send any attributes for any memory holes, just so they
get ignored on the destination.
Message-ID: <20241219144115.2820241-9-david@redhat.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Signed-off-by: David Hildenbrand <david@redhat.com>
A guest OS that supports memory hotplug / memory devices must during
boot be aware of the maximum possible physical memory address that it might
have to handle at a later stage during its runtime.
For example, the maximum possible memory address might be required to
prepare the kernel virtual address space accordingly (e.g., select page
table hierarchy depth).
On s390x there is currently no such mechanism that is compatible with
paravirtualized memory devices, because the whole SCLP interface was
designed around the idea of "storage increments" and "standby memory".
Paravirtualized memory devices we want to support, such as virtio-mem, have
no intersection with any of that, but could co-exist with them in the
future if ever needed.
In particular, a guest OS must never detect and use device memory
without the help of a proper device driver. Device memory must not be
exposed in any firmware-provided memory map (SCLP or diag260 on s390x).
For this reason, these memory devices will be places in memory *above*
the "maximum storage increment" exposed via SCLP.
Let's provide a new diag500 subcode to query the memory limit determined in
s390_memory_init().
Message-ID: <20241219144115.2820241-8-david@redhat.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Signed-off-by: David Hildenbrand <david@redhat.com>
