target/i386: Reset TSCs of parked vCPUs too on VM reset

Since commit 5286c3662294 ("target/i386: properly reset TSC on reset")
QEMU writes the special value of "1" to each online vCPU TSC on VM rese

target/i386: Reset TSCs of parked vCPUs too on VM reset

Since commit 5286c3662294 ("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: 5286c3662294 ("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>
(cherry picked from commit 3f2a05b31ee9ce2ddb6c75a9bc3f5e7f7af9a76f)
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>

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accel/kvm: check for KVM_CAP_MEMORY_ATTRIBUTES on vm

The exact set of available memory attributes can vary by VM. In the
future it might vary depending on enabled capabilities, too. Query the
exte

accel/kvm: check for KVM_CAP_MEMORY_ATTRIBUTES on vm

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>

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accel/kvm: check for KVM_CAP_MULTI_ADDRESS_SPACE on vm

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 sp

accel/kvm: check for KVM_CAP_MULTI_ADDRESS_SPACE on vm

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>

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accel/kvm: check for KVM_CAP_READONLY_MEM on VM

KVM_CAP_READONLY_MEM used to be a global capability, but with the
introduction of AMD SEV-SNP confidential VMs, this extension is not
always available

accel/kvm: check for KVM_CAP_READONLY_MEM on VM

KVM_CAP_READONLY_MEM used to be a global capability, but with the
introduction of AMD SEV-SNP confidential VMs, this extension is not
always available on all VM types [1,2].

Query the extension on the VM level instead of on the KVM level.

[1] https://patchwork.kernel.org/project/kvm/patch/20240809190319.1710470-2-seanjc@google.com/
[2] https://patchwork.kernel.org/project/kvm/patch/20240902144219.3716974-1-erbse.13@gmx.de/

Cc: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Tom Dohrmann <erbse.13@gmx.de>
Link: https://lore.kernel.org/r/20240903062953.3926498-1-erbse.13@gmx.de
Cc: qemu-stable@nongnu.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

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KVM: Rename KVMState->nr_slots to nr_slots_max

This value used to reflect the maximum supported memslots from KVM kernel.
Rename it to be clearer.

Reviewed-by: David Hildenbrand <david@redhat.com>

KVM: Rename KVMState->nr_slots to nr_slots_max

This value used to reflect the maximum supported memslots from KVM kernel.
Rename it to be clearer.

Reviewed-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Peter Xu <peterx@redhat.com>
Link: https://lore.kernel.org/r/20240917163835.194664-5-peterx@redhat.com
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

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KVM: Rename KVMMemoryListener.nr_used_slots to nr_slots_used

This will make all nr_slots counters to be named in the same manner.

Reviewed-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Pe

KVM: Rename KVMMemoryListener.nr_used_slots to nr_slots_used

This will make all nr_slots counters to be named in the same manner.

Reviewed-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Peter Xu <peterx@redhat.com>
Link: https://lore.kernel.org/r/20240917163835.194664-4-peterx@redhat.com
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

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KVM: Define KVM_MEMSLOTS_NUM_MAX_DEFAULT

Make the default max nr_slots a macro, it's only used when KVM reports
nothing.

Reviewed-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Peter Xu <p

KVM: Define KVM_MEMSLOTS_NUM_MAX_DEFAULT

Make the default max nr_slots a macro, it's only used when KVM reports
nothing.

Reviewed-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Peter Xu <peterx@redhat.com>
Link: https://lore.kernel.org/r/20240917163835.194664-3-peterx@redhat.com
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

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KVM: Dynamic sized kvm memslots array

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 slo

KVM: Dynamic sized kvm memslots array

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>

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kvm: Allow kvm_arch_get/put_registers to accept Error**

This is necessary to provide discernible error messages to the caller.

Signed-off-by: Julia Suvorova <jusual@redhat.com>
Reviewed-by: Peter X

kvm: Allow kvm_arch_get/put_registers to accept Error**

This is necessary to provide discernible error messages to the caller.

Signed-off-by: Julia Suvorova <jusual@redhat.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Link: https://lore.kernel.org/r/20240927104743.218468-2-jusual@redhat.com
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

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accel/kvm: refactor dirty ring setup

Refactor setting up of dirty ring code in kvm_init() so that is can be
reused in the future patchsets.

Signed-off-by: Ani Sinha <anisinha@redhat.com>
Link: http

accel/kvm: refactor dirty ring setup

Refactor setting up of dirty ring code in kvm_init() so that is can be
reused in the future patchsets.

Signed-off-by: Ani Sinha <anisinha@redhat.com>
Link: https://lore.kernel.org/r/20240912061838.4501-1-anisinha@redhat.com
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

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kvm: refactor core virtual machine creation into its own function

Refactoring the core logic around KVM_CREATE_VM into its own separate function
so that it can be called from other functions in subs

kvm: refactor core virtual machine creation into its own function

Refactoring the core logic around KVM_CREATE_VM into its own separate function
so that it can be called from other functions in subsequent patches. There is
no functional change in this patch.

CC: pbonzini@redhat.com
CC: zhao1.liu@intel.com
Signed-off-by: Ani Sinha <anisinha@redhat.com>
Link: https://lore.kernel.org/r/20240808113838.1697366-1-anisinha@redhat.com
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

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kvm: replace fprintf with error_report()/printf() in kvm_init()

error_report() is more appropriate for error situations. Replace fprintf with
error_report() and error_printf() as appropriate. Some i

kvm: replace fprintf with error_report()/printf() in kvm_init()

error_report() is more appropriate for error situations. Replace fprintf with
error_report() and error_printf() as appropriate. Some improvement in error
reporting also happens as a part of this change. For example:

From:
$ ./qemu-system-x86_64 --accel kvm
Could not access KVM kernel module: No such file or directory

To:
$ ./qemu-system-x86_64 --accel kvm
qemu-system-x86_64: --accel kvm: Could not access KVM kernel module: No such file or directory

CC: qemu-trivial@nongnu.org
CC: zhao1.liu@intel.com
CC: armbru@redhat.com
Reviewed-by: Zhao Liu <zhao1.liu@intel.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Ani Sinha <anisinha@redhat.com>
Link: https://lore.kernel.org/r/20240828124539.62672-1-anisinha@redhat.com
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

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kvm: Remove unreachable code in kvm_dirty_ring_reaper_thread()

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 t

kvm: Remove unreachable code in kvm_dirty_ring_reaper_thread()

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

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kvm: Make 'mmap_size' be 'int' in kvm_init_vcpu(), do_kvm_destroy_vcpu()

In kvm_init_vcpu()and do_kvm_destroy_vcpu(), the return value from
kvm_ioctl(..., KVM_GET_VCPU_MMAP_SIZE, ...)
is an 'int',

kvm: Make 'mmap_size' be 'int' in kvm_init_vcpu(), do_kvm_destroy_vcpu()

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

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kvm: Use 'unsigned long' for request argument in functions wrapping ioctl()

Change the data type of the ioctl _request_ argument from 'int' to
'unsigned long' for the various accel/kvm functions whi

kvm: Use 'unsigned long' for request argument in functions wrapping ioctl()

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>

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accel/kvm/kvm-all: Fixes the missing break in vCPU unpark logic

Loop should exit prematurely on successfully finding out the parked vCPU (struct
KVMParkedVcpu) in the 'struct KVMState' maintained 'k

accel/kvm/kvm-all: Fixes the missing break in vCPU unpark logic

Loop should exit prematurely on successfully finding out the parked vCPU (struct
KVMParkedVcpu) in the 'struct KVMState' maintained 'kvm_parked_vcpus' list of
parked vCPUs.

Fixes: Coverity CID 1558552
Fixes: 08c3286822 ("accel/kvm: Extract common KVM vCPU {creation,parking} code")
Reported-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Salil Mehta <salil.mehta@huawei.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Gavin Shan <gshan@redhat.com>
Reviewed-by: Zhao Liu <zhao1.liu@intel.com>
Reviewed-by: Igor Mammedov <imammedo@redhat.com>
Message-id: 20240725145132.99355-1-salil.mehta@huawei.com
Suggested-by: Peter Maydell <peter.maydell@linaro.org>
Message-ID: <CAFEAcA-3_d1c7XSXWkFubD-LsW5c5i95e6xxV09r2C9yGtzcdA@mail.gmail.com>
Signed-off-by: Salil Mehta <salil.mehta@huawei.com>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

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accel/kvm: Introduce kvm_create_and_park_vcpu() helper

There are distinct helpers for creating and parking a KVM vCPU.
However, there can be cases where a platform needs to create and
immediately pa

accel/kvm: Introduce kvm_create_and_park_vcpu() helper

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>

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Merge tag 'for-upstream' of https://gitlab.com/bonzini/qemu into staging

* target/i386/kvm: support for reading RAPL MSRs using a helper program
* hpet: emulation improvements

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Merge tag 'for-upstream' of https://gitlab.com/bonzini/qemu into staging

* 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>

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accel/kvm: Extract common KVM vCPU {creation,parking} code

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

accel/kvm: Extract common KVM vCPU {creation,parking} code

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>

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Add support for RAPL MSRs in KVM/Qemu

Starting with the "Sandy Bridge" generation, Intel CPUs provide a RAPL
interface (Running Average Power Limit) for advertising the accumulated
energy consumptio

Add support for RAPL MSRs in KVM/Qemu

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>

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accel/kvm/kvm-all: Fix superfluous trailing semicolon

Signed-off-by: Zhao Liu <zhao1.liu@intel.com>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Alex Bennée <alex.bennee@linaro

accel/kvm/kvm-all: Fix superfluous trailing semicolon

Signed-off-by: Zhao Liu <zhao1.liu@intel.com>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Michael Tokarev <mjt@tls.msk.ru>
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>

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