A bus lock is acquired through either split locked access to writeback
(WB) memory or any locked access to non-WB memory. It is typically >1000
cycles slower than an atomic operation within a cache and can also
disrupts performance on other cores.
Virtual Machines can exploit bus locks to degrade the performance of
system. To address this kind of performance DOS attack coming from the
VMs, bus lock VM exit is introduced in KVM and it can report the bus
locks detected in guest. If enabled in KVM, it would exit to the
userspace to let the user enforce throttling policies once bus locks
acquired in VMs.
The availability of bus lock VM exit can be detected through the
KVM_CAP_X86_BUS_LOCK_EXIT. The returned bitmap contains the potential
policies supported by KVM. The field KVM_BUS_LOCK_DETECTION_EXIT in
bitmap is the only supported strategy at present. It indicates that KVM
will exit to userspace to handle the bus locks.
This patch adds a ratelimit on the bus locks acquired in guest as a
mitigation policy.
Introduce a new field "bus_lock_ratelimit" to record the limited speed
of bus locks in the target VM. The user can specify it through the
"bus-lock-ratelimit" as a machine property. In current implementation,
the default value of the speed is 0 per second, which means no
restrictions on the bus locks.
As for ratelimit on detected bus locks, simply set the ratelimit
interval to 1s and restrict the quota of bus lock occurence to the value
of "bus_lock_ratelimit". A potential alternative is to introduce the
time slice as a property which can help the user achieve more precise
control.
The detail of bus lock VM exit can be found in spec:
https://software.intel.com/content/www/us/en/develop/download/intel-architecture-instruction-set-extensions-programming-reference.html
Signed-off-by: Chenyi Qiang <chenyi.qiang@intel.com>
Message-Id: <20210521043820.29678-1-chenyi.qiang@intel.com>
Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
i386 realizefn code is sensitive to ordering, and recent commits
aimed at refactoring it, splitting accelerator-specific code,
broke assumptions which need to be fixed.
We need to:
* process hyper-v enlightements first, as they assume features
not to be expanded
* only then, expand features
* after expanding features, attempt to check them and modify them in the
accel-specific realizefn code called by cpu_exec_realizefn().
* after the framework has been called via cpu_exec_realizefn,
the code can check for what has or hasn't been set by accel-specific
code, or extend its results, ie:
- check and evenually set code_urev default
- modify cpu->mwait after potentially being set from host CPUID.
- finally check for phys_bits assuming all user and accel-specific
adjustments have already been taken into account.
Fixes: f5cc5a5c ("i386: split cpu accelerators from cpu.c"...)
Fixes: 30565f10 ("cpu: call AccelCPUClass::cpu_realizefn in"...)
Cc: Eduardo Habkost <ehabkost@redhat.com>
Cc: Vitaly Kuznetsov <vkuznets@redhat.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Claudio Fontana <cfontana@suse.de>
Message-Id: <20210603123001.17843-2-cfontana@suse.de>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
* Bump minimum versions of some requirements after removing CentOS 7 support
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Merge remote-tracking branch 'remotes/thuth-gitlab/tags/pull-request-2021-06-02' into staging
* Update the references to some doc files (use *.rst instead of *.txt)
* Bump minimum versions of some requirements after removing CentOS 7 support
# gpg: Signature made Wed 02 Jun 2021 08:12:18 BST
# gpg: using RSA key 27B88847EEE0250118F3EAB92ED9D774FE702DB5
# gpg: issuer "thuth@redhat.com"
# gpg: Good signature from "Thomas Huth <th.huth@gmx.de>" [full]
# gpg: aka "Thomas Huth <thuth@redhat.com>" [full]
# gpg: aka "Thomas Huth <huth@tuxfamily.org>" [full]
# gpg: aka "Thomas Huth <th.huth@posteo.de>" [unknown]
# Primary key fingerprint: 27B8 8847 EEE0 2501 18F3 EAB9 2ED9 D774 FE70 2DB5
* remotes/thuth-gitlab/tags/pull-request-2021-06-02:
configure: bump min required CLang to 6.0 / XCode 10.0
configure: bump min required GCC to 7.5.0
configure: bump min required glib version to 2.56
tests/docker: drop CentOS 7 container
tests/vm: convert centos VM recipe to CentOS 8
crypto: drop used conditional check
crypto: bump min gnutls to 3.5.18, dropping RHEL-7 support
crypto: bump min gcrypt to 1.8.0, dropping RHEL-7 support
crypto: drop back compatibility typedefs for nettle
crypto: bump min nettle to 3.4, dropping RHEL-7 support
patchew: move quick build job from CentOS 7 to CentOS 8 container
block/ssh: Bump minimum libssh version to 0.8.7
docs: fix references to docs/devel/s390-dasd-ipl.rst
docs: fix references to docs/specs/tpm.rst
docs: fix references to docs/devel/build-system.rst
docs: fix references to docs/devel/atomics.rst
docs: fix references to docs/devel/tracing.rst
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Commit e50caf4a5c ("tracing: convert documentation to rST")
converted docs/devel/tracing.txt to docs/devel/tracing.rst.
We still have several references to the old file, so let's fix them
with the following command:
sed -i s/tracing.txt/tracing.rst/ $(git grep -l docs/devel/tracing.txt)
Signed-off-by: Stefano Garzarella <sgarzare@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Message-Id: <20210517151702.109066-2-sgarzare@redhat.com>
Signed-off-by: Thomas Huth <thuth@redhat.com>
There is no need to use vCPU-specific kvm state in hyperv_enabled() check
and we need to do that when feature expansion happens early, before vCPU
specific KVM state is created.
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Reviewed-by: Eduardo Habkost <ehabkost@redhat.com>
Message-Id: <20210422161130.652779-15-vkuznets@redhat.com>
Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
KVM_GET_SUPPORTED_HV_CPUID was made a system wide ioctl which can be called
prior to creating vCPUs and we are going to use that to expand Hyper-V cpu
features early. Use it when it is supported by KVM.
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Reviewed-by: Eduardo Habkost <ehabkost@redhat.com>
Message-Id: <20210422161130.652779-14-vkuznets@redhat.com>
Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
SYNDBG leaves were recently (Linux-5.8) added to KVM but we haven't
updated the expected size of KVM_GET_SUPPORTED_HV_CPUID output in
KVM so we now make serveral tries before succeeding. Update the
default.
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Reviewed-by: Eduardo Habkost <ehabkost@redhat.com>
Message-Id: <20210422161130.652779-13-vkuznets@redhat.com>
Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
hyperv_expand_features() will be called before we create vCPU so
evmcs enablement should go away. hyperv_init_vcpu() looks like the
right place.
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Reviewed-by: Eduardo Habkost <ehabkost@redhat.com>
Message-Id: <20210422161130.652779-11-vkuznets@redhat.com>
Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
The intention is to call hyperv_expand_features() early, before vCPUs
are created and use the acquired data later when we set guest visible
CPUID data.
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Reviewed-by: Eduardo Habkost <ehabkost@redhat.com>
Message-Id: <20210422161130.652779-10-vkuznets@redhat.com>
Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
Just like with cpuid_cache, it makes no sense to call
KVM_GET_SUPPORTED_HV_CPUID more than once and instead of (ab)using
env->features[] and/or trying to keep all the code in one place, it is
better to introduce persistent hv_cpuid_cache and hv_cpuid_get_host()
accessor to it.
Note, hv_cpuid_get_fw() is converted to using hv_cpuid_get_host()
just to be removed later with Hyper-V specific feature words.
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Reviewed-by: Eduardo Habkost <ehabkost@redhat.com>
Message-Id: <20210422161130.652779-9-vkuznets@redhat.com>
Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
Hyper-V feature leaves are weird. We have some of them in
feature_word_info[] array but we don't use feature_word_info
magic to enable them. Neither do we use feature_dependencies[]
mechanism to validate the configuration as it doesn't allign
well with Hyper-V's many-to-many dependency chains. Some of
the feature leaves hold not only feature bits, but also values.
E.g. FEAT_HV_NESTED_EAX contains both features and the supported
Enlightened VMCS range.
Hyper-V features are already represented in 'struct X86CPU' with
uint64_t hyperv_features so duplicating them in env->features adds
little (or zero) benefits. THe other half of Hyper-V emulation features
is also stored with values in hyperv_vendor_id[], hyperv_limits[],...
so env->features[] is already incomplete.
Remove Hyper-V feature leaves from env->features[] completely.
kvm_hyperv_properties[] is converted to using raw CPUID func/reg
pairs for features, this allows us to get rid of hv_cpuid_get_fw()
conversion.
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Reviewed-by: Eduardo Habkost <ehabkost@redhat.com>
Message-Id: <20210422161130.652779-8-vkuznets@redhat.com>
Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
As a preparatory patch to dropping Hyper-V CPUID leaves from
feature_word_info[] stop using env->features[] as a temporary
storage of Hyper-V CPUIDs, just build Hyper-V CPUID leaves directly
from kvm_hyperv_properties[] data.
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Reviewed-by: Eduardo Habkost <ehabkost@redhat.com>
Message-Id: <20210422161130.652779-5-vkuznets@redhat.com>
Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
We have all the required data in X86CPU already and as we are about to
split hyperv_handle_properties() into hyperv_expand_features()/
hyperv_fill_cpuids() we can remove the blind copy. The functional change
is that QEMU won't pass CPUID leaves it doesn't currently know about
to the guest but arguably this is a good change.
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Reviewed-by: Eduardo Habkost <ehabkost@redhat.com>
Message-Id: <20210422161130.652779-4-vkuznets@redhat.com>
Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
There is no need to have this special case: like all other Hyper-V
enlightenments we can just use kernel's supplied value in hv_passthrough
mode.
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Reviewed-by: Eduardo Habkost <ehabkost@redhat.com>
Message-Id: <20210422161130.652779-3-vkuznets@redhat.com>
Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
When cpu->hyperv_vendor is not set manually we default to "Microsoft Hv"
and in 'hv_passthrough' mode we get the information from the host. This
information is stored in cpu->hyperv_vendor_id[] array but we don't update
cpu->hyperv_vendor string so e.g. QMP's query-cpu-model-expansion output
is incorrect.
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Reviewed-by: Eduardo Habkost <ehabkost@redhat.com>
Message-Id: <20210422161130.652779-2-vkuznets@redhat.com>
Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
It's very easy to mistakenly extend kvm_default_props to include
features that require a kernel version that's too recent. Add a
comment warning about that, pointing to the documentation file
where the minimum kernel version for KVM is documented.
Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Message-Id: <20200925211021.4158567-1-ehabkost@redhat.com>
Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
overall, all devices' realize functions take an Error **errp, but return void.
hw/core/qdev.c code, which realizes devices, therefore does:
local_err = NULL;
dc->realize(dev, &local_err);
if (local_err != NULL) {
goto fail;
}
However, we can improve at least accel_cpu to return a meaningful bool value.
Signed-off-by: Claudio Fontana <cfontana@suse.de>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20210322132800.7470-9-cfontana@suse.de>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
i386 is the first user of AccelCPUClass, allowing to split
cpu.c into:
cpu.c cpuid and common x86 cpu functionality
host-cpu.c host x86 cpu functions and "host" cpu type
kvm/kvm-cpu.c KVM x86 AccelCPUClass
hvf/hvf-cpu.c HVF x86 AccelCPUClass
tcg/tcg-cpu.c TCG x86 AccelCPUClass
Signed-off-by: Claudio Fontana <cfontana@suse.de>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
[claudio]:
Rebased on commit b8184135 ("target/i386: allow modifying TCG phys-addr-bits")
Signed-off-by: Claudio Fontana <cfontana@suse.de>
Message-Id: <20210322132800.7470-5-cfontana@suse.de>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
KVM doesn't fully support Hyper-V reenlightenment notifications on
migration. In particular, it doesn't support emulating TSC frequency
of the source host by trapping all TSC accesses so unless TSC scaling
is supported on the destination host and KVM_SET_TSC_KHZ succeeds, it
is unsafe to proceed with migration.
KVM_SET_TSC_KHZ is called from two sites: kvm_arch_init_vcpu() and
kvm_arch_put_registers(). The later (intentionally) doesn't propagate
errors allowing migrations to succeed even when TSC scaling is not
supported on the destination. This doesn't suit 're-enlightenment'
use-case as we have to guarantee that TSC frequency stays constant.
Require 'tsc-frequency=' command line option to be specified for successful
migration when re-enlightenment was enabled by the guest.
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Message-Id: <20210319123801.1111090-1-vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
The 'running' argument from VMChangeStateHandler does not require
other value than 0 / 1. Make it a plain boolean.
Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Acked-by: David Gibson <david@gibson.dropbear.id.au>
Message-Id: <20210111152020.1422021-3-philmd@redhat.com>
Signed-off-by: Laurent Vivier <laurent@vivier.eu>
If kvm_arch_remove_sw_breakpoint finds that a software breakpoint does not
have an INT3 instruction, it fails. This can happen if one sets a
software breakpoint in a kernel module and then reloads it. gdb then
thinks the breakpoint cannot be deleted and there is no way to add it
back.
Suggested-by: Maxim Levitsky <mlevitsk@redhat.com>
Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
SMM is not currently supported for an SEV-ES guest by KVM. Change the SMM
capability check from a KVM-wide check to a per-VM check in order to have
a finer-grained SMM capability check.
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Richard Henderson <richard.henderson@linaro.org>
Cc: Eduardo Habkost <ehabkost@redhat.com>
Suggested-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
Reviewed-by: Venu Busireddy <venu.busireddy@oracle.com>
Message-Id: <f851903809e9d4e6a22d5dfd738dac8da991e28d.1611682609.git.thomas.lendacky@amd.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
An SEV-ES guest does not allow register state to be altered once it has
been measured. When an SEV-ES guest issues a reboot command, Qemu will
reset the vCPU state and resume the guest. This will cause failures under
SEV-ES. Prevent that from occuring by introducing an arch-specific
callback that returns a boolean indicating whether vCPUs are resettable.
Cc: Peter Maydell <peter.maydell@linaro.org>
Cc: Aurelien Jarno <aurelien@aurel32.net>
Cc: Jiaxun Yang <jiaxun.yang@flygoat.com>
Cc: Aleksandar Rikalo <aleksandar.rikalo@syrmia.com>
Cc: David Gibson <david@gibson.dropbear.id.au>
Cc: David Hildenbrand <david@redhat.com>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
Reviewed-by: Venu Busireddy <venu.busireddy@oracle.com>
Message-Id: <1ac39c441b9a3e970e9556e1cc29d0a0814de6fd.1611682609.git.thomas.lendacky@amd.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
When SEV-ES is enabled, it is not possible modify the guests register
state after it has been initially created, encrypted and measured.
Normally, an INIT-SIPI-SIPI request is used to boot the AP. However, the
hypervisor cannot emulate this because it cannot update the AP register
state. For the very first boot by an AP, the reset vector CS segment
value and the EIP value must be programmed before the register has been
encrypted and measured. Search the guest firmware for the guest for a
specific GUID that tells Qemu the value of the reset vector to use.
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Marcel Apfelbaum <marcel.apfelbaum@gmail.com>
Cc: Richard Henderson <richard.henderson@linaro.org>
Cc: Eduardo Habkost <ehabkost@redhat.com>
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
Message-Id: <22db2bfb4d6551aed661a9ae95b4fdbef613ca21.1611682609.git.thomas.lendacky@amd.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
PKS introduces MSR IA32_PKRS(0x6e1) to manage the supervisor protection
key rights. Page access and writes can be managed via the MSR update
without TLB flushes when permissions change.
Add the support to save/load IA32_PKRS MSR in guest.
Signed-off-by: Chenyi Qiang <chenyi.qiang@intel.com>
Message-Id: <20210205083325.13880-2-chenyi.qiang@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
While we've abstracted some (potential) differences between mechanisms for
securing guest memory, the initialization is still specific to SEV. Given
that, move it into x86's kvm_arch_init() code, rather than the generic
kvm_init() code.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Reviewed-by: Greg Kurz <groug@kaod.org>
As a preparation to expanding Hyper-V CPU features early, move
hyperv_limits initialization to x86_cpu_realizefn().
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Message-Id: <20201119103221.1665171-5-vkuznets@redhat.com>
Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
As a preparation to expanding Hyper-V CPU features early, move
hyperv_version_id initialization to x86_cpu_realizefn().
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Message-Id: <20201119103221.1665171-4-vkuznets@redhat.com>
Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
As a preparation to expanding Hyper-V CPU features early, move
hyperv_interface_id initialization to x86_cpu_realizefn().
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Message-Id: <20201119103221.1665171-3-vkuznets@redhat.com>
Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
As a preparation to expanding Hyper-V CPU features early, move
hyperv_vendor_id initialization to x86_cpu_realizefn(). Introduce
x86_cpu_hyperv_realize() to not not pollute x86_cpu_realizefn()
itself.
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Message-Id: <20201119103221.1665171-2-vkuznets@redhat.com>
Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
