Unfortunately "system/accel-ops.h" handlers are not only
system-specific. For example, the cpu_reset_hold() hook
is part of the vCPU creation, after it is realized.
Mechanical rename to drop 'system' using:
$ sed -i -e s_system/accel-ops.h_accel/accel-cpu-ops.h_g \
$(git grep -l system/accel-ops.h)
Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Zhao Liu <zhao1.liu@intel.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20250703173248.44995-38-philmd@linaro.org>
Since commit 126e7f7803 ("kvm: require KVM_CAP_IOEVENTFD and
KVM_CAP_IOEVENTFD_ANY_LENGTH") we require at least kernel 4.5 to
be able to use KVM. Adjust the upgrade_note accordingly.
While we're at it, remove the text about kvm-kmod and the
SourceForge URL since this is not actively maintained anymore.
Fixes: 126e7f7803 ("kvm: require KVM_CAP_IOEVENTFD and KVM_CAP_IOEVENTFD_ANY_LENGTH")
Signed-off-by: Thomas Huth <thuth@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Michael Tokarev <mjt@tls.msk.ru>
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
A new field, attributes, was introduced in RAMBlock to link to a
RamBlockAttributes object, which centralizes all guest_memfd related
information (such as fd and status bitmap) within a RAMBlock.
Create and initialize the RamBlockAttributes object upon ram_block_add().
Meanwhile, register the object in the target RAMBlock's MemoryRegion.
After that, guest_memfd-backed RAMBlock is associated with the
RamDiscardManager interface, and the users can execute RamDiscardManager
specific handling. For example, VFIO will register the
RamDiscardListener and get notifications when the state_change() helper
invokes.
As coordinate discarding of RAM with guest_memfd is now supported, only
block uncoordinated discard.
Tested-by: Alexey Kardashevskiy <aik@amd.com>
Reviewed-by: Alexey Kardashevskiy <aik@amd.com>
Acked-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Chenyi Qiang <chenyi.qiang@intel.com>
Link: https://lore.kernel.org/r/20250612082747.51539-6-chenyi.qiang@intel.com
Signed-off-by: Peter Xu <peterx@redhat.com>
A page state change is typically followed by an access of the page(s) and
results in another VMEXIT in order to map the page into the nested page
table. Depending on the size of page state change request, this can
generate a number of additional VMEXITs. For example, under SNP, when
Linux is utilizing lazy memory acceptance, memory is typically accepted in
4M chunks. A page state change request is submitted to mark the pages as
private, followed by validation of the memory. Since the guest_memfd
currently only supports 4K pages, each page validation will result in
VMEXIT to map the page, resulting in 1024 additional exits.
When performing a page state change, invoke KVM_PRE_FAULT_MEMORY for the
size of the page state change in order to pre-map the pages and avoid the
additional VMEXITs. This helps speed up boot times.
Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
Link: https://lore.kernel.org/r/f5411c42340bd2f5c14972551edb4e959995e42b.1743193824.git.thomas.lendacky@amd.com
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Convert the existing includes with
sed -i ,exec/memory.h,system/memory.h,g
Move the include within cpu-all.h into a !CONFIG_USER_ONLY block.
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Pierrick Bouvier <pierrick.bouvier@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Commit 3f2a05b31e ("target/i386: Reset TSCs of parked vCPUs too on VM
reset") introduced a way to reset TSCs of parked vCPUs during VM reset to
prevent them getting desynchronized with the online vCPUs and therefore
causing the KVM PV clock to lose PVCLOCK_TSC_STABLE_BIT.
The way this was done was by registering a parked vCPU-specific QEMU reset
callback via qemu_register_reset().
However, it turns out that on particularly device-rich VMs QEMU reset
callbacks can take a long time to execute (which isn't surprising,
considering that they involve resetting all of VM devices).
In particular, their total runtime can exceed the 1-second TSC
synchronization window introduced in KVM commit 5d3cb0f6a8e3 ("KVM:
Improve TSC offset matching").
Since the TSCs of online vCPUs are only reset from "synchronize_post_reset"
AccelOps handler (which runs after all qemu_register_reset() handlers) this
essentially makes that fix ineffective on these VMs.
The easiest way to guarantee that these parked vCPUs are reset at the same
time as the online ones (regardless how long it takes for VM devices to
reset) is to piggyback on post-reset vCPU synchronization handler for one
of online vCPUs - as there is no generic post-reset AccelOps handler that
isn't per-vCPU.
The first online vCPU was selected for that since it is easily available
under "first_cpu" define.
This does not create an ordering issue since the order of vCPU TSC resets
does not matter.
Fixes: 3f2a05b31e ("target/i386: Reset TSCs of parked vCPUs too on VM reset")
Signed-off-by: Maciej S. Szmigiero <maciej.szmigiero@oracle.com>
Link: https://lore.kernel.org/r/e8b85a5915f79aa177ca49eccf0e9b534470c1cd.1743099810.git.maciej.szmigiero@oracle.com
Cc: qemu-stable@nongnu.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
The heavily imported "system/cpus.h" header includes "accel-ops.h"
to get AccelOpsClass type declaration. Reduce headers pressure by
forward declaring it in "qemu/typedefs.h", where we already
declare the AccelCPUState type.
Reduce "system/cpus.h" inclusions by only including
"system/accel-ops.h" when necessary.
Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20250123234415.59850-14-philmd@linaro.org>
Accel & Exec patch queue
- Ignore writes to CNTP_CTL_EL0 on HVF ARM (Alexander)
- Add '-d invalid_mem' logging option (Zoltan)
- Create QOM containers explicitly (Peter)
- Rename sysemu/ -> system/ (Philippe)
- Re-orderning of include/exec/ headers (Philippe)
Move a lot of declarations from these legacy mixed bag headers:
. "exec/cpu-all.h"
. "exec/cpu-common.h"
. "exec/cpu-defs.h"
. "exec/exec-all.h"
. "exec/translate-all"
to these more specific ones:
. "exec/page-protection.h"
. "exec/translation-block.h"
. "user/cpu_loop.h"
. "user/guest-host.h"
. "user/page-protection.h"
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# gpg: WARNING: This key is not certified with a trusted signature!
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# Primary key fingerprint: FAAB E75E 1291 7221 DCFD 6BB2 E3E3 2C2C DEAD C0DE
* tag 'exec-20241220' of https://github.com/philmd/qemu: (59 commits)
util/qemu-timer: fix indentation
meson: Do not define CONFIG_DEVICES on user emulation
system/accel-ops: Remove unnecessary 'exec/cpu-common.h' header
system/numa: Remove unnecessary 'exec/cpu-common.h' header
hw/xen: Remove unnecessary 'exec/cpu-common.h' header
target/mips: Drop left-over comment about Jazz machine
target/mips: Remove tswap() calls in semihosting uhi_fstat_cb()
target/xtensa: Remove tswap() calls in semihosting simcall() helper
accel/tcg: Un-inline translator_is_same_page()
accel/tcg: Include missing 'exec/translation-block.h' header
accel/tcg: Move tcg_cflags_has/set() to 'exec/translation-block.h'
accel/tcg: Restrict curr_cflags() declaration to 'internal-common.h'
qemu/coroutine: Include missing 'qemu/atomic.h' header
exec/translation-block: Include missing 'qemu/atomic.h' header
accel/tcg: Declare cpu_loop_exit_requested() in 'exec/cpu-common.h'
exec/cpu-all: Include 'cpu.h' earlier so MMU_USER_IDX is always defined
target/sparc: Move sparc_restore_state_to_opc() to cpu.c
target/sparc: Uninline cpu_get_tb_cpu_state()
target/loongarch: Declare loongarch_cpu_dump_state() locally
user: Move various declarations out of 'exec/exec-all.h'
...
Conflicts:
hw/char/riscv_htif.c
hw/intc/riscv_aplic.c
target/s390x/cpu.c
Apply sysemu header path changes to not in the pull request.
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Headers in include/sysemu/ are not only related to system
*emulation*, they are also used by virtualization. Rename
as system/ which is clearer.
Files renamed manually then mechanical change using sed tool.
Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Tested-by: Lei Yang <leiyang@redhat.com>
Message-Id: <20241203172445.28576-1-philmd@linaro.org>
Since commit 5286c36622 ("target/i386: properly reset TSC on reset")
QEMU writes the special value of "1" to each online vCPU TSC on VM reset
to reset it.
However parked vCPUs don't get that handling and due to that their TSCs
get desynchronized when the VM gets reset.
This in turn causes KVM to turn off PVCLOCK_TSC_STABLE_BIT in its exported
PV clock.
Note that KVM has no understanding of vCPU being currently parked.
Without PVCLOCK_TSC_STABLE_BIT the sched clock is marked unstable in
the guest's kvm_sched_clock_init().
This causes a performance regressions to show in some tests.
Fix this issue by writing the special value of "1" also to TSCs of parked
vCPUs on VM reset.
Reproducing the issue:
1) Boot a VM with "-smp 2,maxcpus=3" or similar
2) device_add host-x86_64-cpu,id=vcpu,node-id=0,socket-id=0,core-id=2,thread-id=0
3) Wait a few seconds
4) device_del vcpu
5) Inside the VM run:
# echo "t" >/proc/sysrq-trigger; dmesg | grep sched_clock_stable
Observe the sched_clock_stable() value is 1.
6) Reboot the VM
7) Once the VM boots once again run inside it:
# echo "t" >/proc/sysrq-trigger; dmesg | grep sched_clock_stable
Observe the sched_clock_stable() value is now 0.
Fixes: 5286c36622 ("target/i386: properly reset TSC on reset")
Signed-off-by: Maciej S. Szmigiero <maciej.szmigiero@oracle.com>
Link: https://lore.kernel.org/r/5a605a88e9a231386dc803c60f5fed9b48108139.1734014926.git.maciej.szmigiero@oracle.com
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
In case of incorrect parameters, kvm_convert_memory() was returning
-1 instead of -EINVAL. The guest won't notice because it will move
anyway to RUN_STATE_INTERNAL_ERROR, but fix this for consistency and
clarity.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
The exact set of available memory attributes can vary by VM. In the
future it might vary depending on enabled capabilities, too. Query the
extension on the VM level instead of on the KVM level, and only after
architecture-specific initialization.
Inspired by an analogous patch by Tom Dohrmann.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
KVM_CAP_MULTI_ADDRESS_SPACE used to be a global capability, but with the
introduction of AMD SEV-SNP confidential VMs, the number of address spaces
can vary by VM type.
Query the extension on the VM level instead of on the KVM level.
Inspired by an analogous patch by Tom Dohrmann.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Zhiyi reported an infinite loop issue in VFIO use case. The cause of that
was a separate discussion, however during that I found a regression of
dirty sync slowness when profiling.
Each KVMMemoryListerner maintains an array of kvm memslots. Currently it's
statically allocated to be the max supported by the kernel. However after
Linux commit 4fc096a99e ("KVM: Raise the maximum number of user memslots"),
the max supported memslots reported now grows to some number large enough
so that it may not be wise to always statically allocate with the max
reported.
What's worse, QEMU kvm code still walks all the allocated memslots entries
to do any form of lookups. It can drastically slow down all memslot
operations because each of such loop can run over 32K times on the new
kernels.
Fix this issue by making the memslots to be allocated dynamically.
Here the initial size was set to 16 because it should cover the basic VM
usages, so that the hope is the majority VM use case may not even need to
grow at all (e.g. if one starts a VM with ./qemu-system-x86_64 by default
it'll consume 9 memslots), however not too large to waste memory.
There can also be even better way to address this, but so far this is the
simplest and should be already better even than before we grow the max
supported memslots. For example, in the case of above issue when VFIO was
attached on a 32GB system, there are only ~10 memslots used. So it could
be good enough as of now.
In the above VFIO context, measurement shows that the precopy dirty sync
shrinked from ~86ms to ~3ms after this patch applied. It should also apply
to any KVM enabled VM even without VFIO.
NOTE: we don't have a FIXES tag for this patch because there's no real
commit that regressed this in QEMU. Such behavior existed for a long time,
but only start to be a problem when the kernel reports very large
nr_slots_max value. However that's pretty common now (the kernel change
was merged in 2021) so we attached cc:stable because we'll want this change
to be backported to stable branches.
Cc: qemu-stable <qemu-stable@nongnu.org>
Reported-by: Zhiyi Guo <zhguo@redhat.com>
Tested-by: Zhiyi Guo <zhguo@redhat.com>
Signed-off-by: Peter Xu <peterx@redhat.com>
Acked-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Fabiano Rosas <farosas@suse.de>
Link: https://lore.kernel.org/r/20240917163835.194664-2-peterx@redhat.com
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
The code at the tail end of the loop in kvm_dirty_ring_reaper_thread()
is unreachable, because there is no way for execution to leave the
loop. Replace it with a g_assert_not_reached().
(The code has always been unreachable, right from the start
when the function was added in commit b4420f198dd8.)
Resolves: Coverity CID 1547687
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Message-id: 20240815131206.3231819-3-peter.maydell@linaro.org
In kvm_init_vcpu()and do_kvm_destroy_vcpu(), the return value from
kvm_ioctl(..., KVM_GET_VCPU_MMAP_SIZE, ...)
is an 'int', but we put it into a 'long' logal variable mmap_size.
Coverity then complains that there might be a truncation when we copy
that value into the 'int ret' which we use for returning a value in
an error-exit codepath. This can't ever actually overflow because
the value was in an 'int' to start with, but it makes more sense
to use 'int' for mmap_size so we don't do the widen-then-narrow
sequence in the first place.
Resolves: Coverity CID 1547515
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Message-id: 20240815131206.3231819-2-peter.maydell@linaro.org
Change the data type of the ioctl _request_ argument from 'int' to
'unsigned long' for the various accel/kvm functions which are
essentially wrappers around the ioctl() syscall.
The correct type for ioctl()'s 'request' argument is confused:
* POSIX defines the request argument as 'int'
* glibc uses 'unsigned long' in the prototype in sys/ioctl.h
* the glibc info documentation uses 'int'
* the Linux manpage uses 'unsigned long'
* the Linux implementation of the syscall uses 'unsigned int'
If we wrap ioctl() with another function which uses 'int' as the
type for the request argument, then requests with the 0x8000_0000
bit set will be sign-extended when the 'int' is cast to
'unsigned long' for the call to ioctl().
On x86_64 one such example is the KVM_IRQ_LINE_STATUS request.
Bit requests with the _IOC_READ direction bit set, will have the high
bit set.
Fortunately the Linux Kernel truncates the upper 32bit of the request
on 64bit machines (because it uses 'unsigned int', and see also Linus
Torvalds' comments in
https://sourceware.org/bugzilla/show_bug.cgi?id=14362 )
so this doesn't cause active problems for us. However it is more
consistent to follow the glibc ioctl() prototype when we define
functions that are essentially wrappers around ioctl().
This resolves a Coverity issue where it points out that in
kvm_get_xsave() we assign a value (KVM_GET_XSAVE or KVM_GET_XSAVE2)
to an 'int' variable which can't hold it without overflow.
Resolves: Coverity CID 1547759
Signed-off-by: Johannes Stoelp <johannes.stoelp@gmail.com>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-id: 20240815122747.3053871-1-peter.maydell@linaro.org
[PMM: Rebased patch, adjusted commit message, included note about
Coverity fix, updated the type of the local var in kvm_get_xsave,
updated the comment in the KVMState struct definition]
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
There are distinct helpers for creating and parking a KVM vCPU.
However, there can be cases where a platform needs to create and
immediately park the vCPU during early stages of vcpu init which
can later be reused when vcpu thread gets initialized. This would
help detect failures with kvm_create_vcpu at an early stage.
Suggested-by: Nicholas Piggin <npiggin@gmail.com>
Reviewed-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Harsh Prateek Bora <harshpb@linux.ibm.com>
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
* target/i386/kvm: support for reading RAPL MSRs using a helper program
* hpet: emulation improvements
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* tag 'for-upstream' of https://gitlab.com/bonzini/qemu:
hpet: avoid timer storms on periodic timers
hpet: store full 64-bit target value of the counter
hpet: accept 64-bit reads and writes
hpet: place read-only bits directly in "new_val"
hpet: remove unnecessary variable "index"
hpet: ignore high bits of comparator in 32-bit mode
hpet: fix and cleanup persistence of interrupt status
Add support for RAPL MSRs in KVM/Qemu
tools: build qemu-vmsr-helper
qio: add support for SO_PEERCRED for socket channel
target/i386: do not crash if microvm guest uses SGX CPUID leaves
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
KVM vCPU creation is done once during the vCPU realization when Qemu vCPU thread
is spawned. This is common to all the architectures as of now.
Hot-unplug of vCPU results in destruction of the vCPU object in QOM but the
corresponding KVM vCPU object in the Host KVM is not destroyed as KVM doesn't
support vCPU removal. Therefore, its representative KVM vCPU object/context in
Qemu is parked.
Refactor architecture common logic so that some APIs could be reused by vCPU
Hotplug code of some architectures likes ARM, Loongson etc. Update new/old APIs
with trace events. New APIs qemu_{create,park,unpark}_vcpu() can be externally
called. No functional change is intended here.
Signed-off-by: Salil Mehta <salil.mehta@huawei.com>
Reviewed-by: Gavin Shan <gshan@redhat.com>
Tested-by: Vishnu Pajjuri <vishnu@os.amperecomputing.com>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Tested-by: Xianglai Li <lixianglai@loongson.cn>
Tested-by: Miguel Luis <miguel.luis@oracle.com>
Reviewed-by: Shaoqin Huang <shahuang@redhat.com>
Reviewed-by: Vishnu Pajjuri <vishnu@os.amperecomputing.com>
Reviewed-by: Nicholas Piggin <npiggin@gmail.com>
Tested-by: Zhao Liu <zhao1.liu@intel.com>
Reviewed-by: Zhao Liu <zhao1.liu@intel.com>
Reviewed-by: Harsh Prateek Bora <harshpb@linux.ibm.com>
Reviewed-by: Igor Mammedov <imammedo@redhat.com>
Message-Id: <20240716111502.202344-2-salil.mehta@huawei.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Starting with the "Sandy Bridge" generation, Intel CPUs provide a RAPL
interface (Running Average Power Limit) for advertising the accumulated
energy consumption of various power domains (e.g. CPU packages, DRAM,
etc.).
The consumption is reported via MSRs (model specific registers) like
MSR_PKG_ENERGY_STATUS for the CPU package power domain. These MSRs are
64 bits registers that represent the accumulated energy consumption in
micro Joules. They are updated by microcode every ~1ms.
For now, KVM always returns 0 when the guest requests the value of
these MSRs. Use the KVM MSR filtering mechanism to allow QEMU handle
these MSRs dynamically in userspace.
To limit the amount of system calls for every MSR call, create a new
thread in QEMU that updates the "virtual" MSR values asynchronously.
Each vCPU has its own vMSR to reflect the independence of vCPUs. The
thread updates the vMSR values with the ratio of energy consumed of
the whole physical CPU package the vCPU thread runs on and the
thread's utime and stime values.
All other non-vCPU threads are also taken into account. Their energy
consumption is evenly distributed among all vCPUs threads running on
the same physical CPU package.
To overcome the problem that reading the RAPL MSR requires priviliged
access, a socket communication between QEMU and the qemu-vmsr-helper is
mandatory. You can specified the socket path in the parameter.
This feature is activated with -accel kvm,rapl=true,path=/path/sock.sock
Actual limitation:
- Works only on Intel host CPU because AMD CPUs are using different MSR
adresses.
- Only the Package Power-Plane (MSR_PKG_ENERGY_STATUS) is reported at
the moment.
Signed-off-by: Anthony Harivel <aharivel@redhat.com>
Link: https://lore.kernel.org/r/20240522153453.1230389-4-aharivel@redhat.com
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
