During migrations, after each iteration, cpu_throttle_set() is called,
which irrespective of input, re-arms the timer according to value of
new_throttle_pct. This causes cpu_throttle_thread() to be delayed in
getting scheduled and consqeuntly lets guest run for more time than what
the throttle value should allow. This leads to spikes in guest throughput
at high cpu-throttle percentage whenever cpu_throttle_set() is called.
A solution would be not to modify the timer immediately in
cpu_throttle_set(), instead, only modify throttle_percentage so that the
throttle would automatically adjust to the required percentage when
cpu_throttle_timer_tick() is invoked.
Manually tested the patch using following configuration:
Guest:
Centos7 (3.10.0-123.el7.x86_64)
Total Memory - 64GB , CPUs - 16
Tool used - stress (1.0.4)
Workload - stress --vm 32 --vm-bytes 1G --vm-keep
Migration Parameters:
Network Bandwidth - 500MBPS
cpu-throttle-initial - 99
Results:
With timer_mod(): fails to converge, continues indefinitely
Without timer_mod(): converges in 249 sec
Signed-off-by: Utkarsh Tripathi <utkarsh.tripathi@nutanix.com>
Message-Id: <1609420384-119407-1-git-send-email-utkarsh.tripathi@nutanix.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This patch enables using rng-builtin with record/replay
by making the callbacks deterministic.
Signed-off-by: Pavel Dovgalyuk <Pavel.Dovgalyuk@ispras.ru>
Message-Id: <161233201286.170686.7858208964037376305.stgit@pasha-ThinkPad-X280>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Before the change /usr/share/qemu/firmware/50-edk2-x86_64-secure.json
contained the relative path:
"filename": "share/qemu/edk2-x86_64-secure-code.fd",
"filename": "share/qemu/edk2-i386-vars.fd",
After then change the paths are absolute:
"filename": "/usr/share/qemu/edk2-x86_64-secure-code.fd",
"filename": "/usr/share/qemu/edk2-i386-vars.fd",
The regression appeared in qemu-5.2.0 (seems to be related
to meson port).
CC: Paolo Bonzini <pbonzini@redhat.com>
CC: "Marc-André Lureau" <marcandre.lureau@redhat.com>
CC: "Philippe Mathieu-Daudé" <philmd@redhat.com>
Bug: https://bugs.gentoo.org/766743
Bug: https://bugs.launchpad.net/qemu/+bug/1913012
Signed-off-by: Jannik Glückert <jannik.glueckert@gmail.com>
Signed-off-by: Sergei Trofimovich <slyfox@gentoo.org>
Message-Id: <20210131143434.2513363-1-slyfox@gentoo.org>
Cc: qemu-stable@nongnu.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Sometimes interrupt event comes at the same time with
the virtual timers. In this case replay tries to proceed
the timers, because deadline for them is zero.
This patch allows processing interrupts and exceptions
by entering the vCPU execution loop, when deadline is zero,
but checkpoint associated with virtual timers is not ready
to be replayed.
Signed-off-by: Pavel Dovgalyuk <Pavel.Dovgalyuk@ispras.ru>
Message-Id: <161216312794.2030770.1709657858900983160.stgit@pasha-ThinkPad-X280>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
The kvm_vm_ioctl() wrapper already returns -errno if the ioctl itself
returned -1, so the callers of kvm_vm_ioctl() should not check for -1
but for a value < 0 instead.
This problem has been fixed once already in commit b533f658a9
but that commit missed that the ENOENT error code is not fatal for
this ioctl, so the commit has been reverted in commit 50212d6346
since the problem occurred close to a pending release at that point
in time. The plan was to fix it properly after the release, but it
seems like this has been forgotten. So let's do it now finally instead.
Resolves: https://bugs.launchpad.net/qemu/+bug/1294227
Signed-off-by: Thomas Huth <thuth@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Message-Id: <20210129084354.42928-1-thuth@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Message-Id: <20210122204441.2145197-13-philmd@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Message-Id: <20210122204441.2145197-12-philmd@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Message-Id: <20210122204441.2145197-11-philmd@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Beside a CPU device, user-mode emulation doesn't access
anything else from qdev subsystem.
Tools don't need anything from qdev.
Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Message-Id: <20210122204441.2145197-10-philmd@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Message-Id: <20210122204441.2145197-9-philmd@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Message-Id: <20210122204441.2145197-8-philmd@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
The trace_events_subdirs array is split in two different
locations, merge it as one.
Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Claudio Fontana <cfontana@suse.de>
Message-Id: <20210122204441.2145197-7-philmd@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Avoid generating module_block.h and block-gen.c if we are
not going to use them.
Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Message-Id: <20210122204441.2145197-6-philmd@redhat.com>
[Extend to nearby files and directories. - Paolo]
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Message-Id: <20210122204441.2145197-4-philmd@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Suggested-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <20210122204441.2145197-3-philmd@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Some new users get confused with 'TCG' and 'TCI', and enable TCI
support expecting to enable TCG.
Emit a warning when native TCG backend is available on the
host architecture, mentioning this is a suboptimal configuration.
Reviewed-by: Thomas Huth <thuth@redhat.com>
Suggested-by: Daniel Berrangé <berrange@redhat.com>
Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Message-Id: <20210125144530.2837481-5-philmd@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Reviewed-by: Stefan Weil <sw@weilnetz.de>
Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Message-Id: <20210125144530.2837481-4-philmd@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Users might want to enable all features, without realizing some
features have negative effect. Mention the TCI feature is slow
and experimental, hoping it will be selected knowingly.
Suggested-by: Thomas Huth <thuth@redhat.com>
Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Message-Id: <20210125144530.2837481-3-philmd@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Protection Keys for Supervisor-mode pages is a simple extension of
the PKU feature that QEMU already implements. For supervisor-mode
pages, protection key restrictions come from a new MSR. The MSR
has no XSAVE state associated to it.
PKS is only respected in long mode. However, in principle it is
possible to set the MSR even outside long mode, and in fact
even the XSAVE state for PKRU could be set outside long mode
using XRSTOR. So do not limit the migration subsections for
PKRU and PKRS to long mode.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This patch fixes a translation bug for a subset of x86 BMI instructions
such as the following:
c4 e2 f9 f7 c0 shlxq %rax, %rax, %rax
Currently, these incorrectly generate an undefined instruction exception
when SSE is disabled via CR4, while instructions like "shrxq" work fine.
The problem appears to be related to BMI instructions encoded using VEX
and with a mandatory prefix of "0x66" (data). Instructions with this
data prefix (such as shlxq) are currently rejected. Instructions with
other mandatory prefixes (such as shrxq) translate as expected.
This patch removes the incorrect check in "gen_sse" that causes the
exception to be generated. For the non-BMI cases, the check is
redundant: prefixes are already checked at line 3696.
Buglink: https://bugs.launchpad.net/qemu/+bug/1748296
Signed-off-by: David Greenaway <dgreenaway@google.com>
Message-Id: <20210114063958.1508050-1-dgreenaway@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Add 'initialized' field and use it to avoid touching event notifiers which are
either not initialized or if their initialization failed.
This is somewhat a hack, but it seems the less intrusive way to make
virtio code deal with event notifiers that failed initialization.
Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com>
Message-Id: <20201217150040.906961-4-mlevitsk@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Count number of queues that we initialized and only deinitialize these that we
initialized successfully.
Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com>
Message-Id: <20201217150040.906961-3-mlevitsk@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
No sense outputting the qemu-ga and qemu-ga-ref man pages when the guest
agent binary itself is disabled. This mirrors behaviour from before the
meson switch.
Signed-off-by: Stefan Reiter <s.reiter@proxmox.com>
Message-Id: <20210128145801.14384-1-s.reiter@proxmox.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Qiuhao Li <Qiuhao.Li@outlook.com>
Message-Id: <SYCPR01MB3502E9F6EB06DEDCD484F738FCBA9@SYCPR01MB3502.ausprd01.prod.outlook.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Newer AMD CPUs will add CPUID_0x8000000A_EDX[28] bit, which indicates
that SVM instructions (VMRUN/VMSAVE/VMLOAD) will trigger #VMEXIT before
CPU checking their EAX against reserved memory regions. This change will
allow the hypervisor to avoid intercepting #GP and emulating SVM
instructions. KVM turns on this CPUID bit for nested VMs. In order to
support it, let us populate this bit, along with other SVM feature bits,
in FEAT_SVM.
Signed-off-by: Wei Huang <wei.huang2@amd.com>
Message-Id: <20210126202456.589932-1-wei.huang2@amd.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
If the link test failed, compilation proceeded with RBD disabled,
even if --enable-rbd was used on the configure command line.
Fix that.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Meson's "static" argument to cc.find_library is a tri-state. By default
Meson *prefers* a shared library, which basically means using -l to
look for it; instead, "static: false" *requires* a shared library. Of
course, "static: true" requires a static library, which is all good
for --enable-static builds.
For --disable-static, "static: false" is rarely desirable; it does not
match what the configure script used to do and the test is more complex
(and harder to debug if it fails, which was reported by Peter Lieven
for librbd).
Reported-by: Peter Lieven <pl@kamp.de>
Tested-by: Peter Lieven <pl@kamp.de>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Add documentation for '-machine memory-backend' CLI option and
how to use it.
And document that x-use-canonical-path-for-ramblock-id,
is considered to be stable to make sure it won't go away by accident.
x- was intended for unstable/iternal properties, and not supposed to
be stable option. However it's too late to rename (drop x-)
it as it would mean that users will have to mantain both
x-use-canonical-path-for-ramblock-id (for QEMU 5.0-5.2) versions
and prefix-less for later versions.
Signed-off-by: Igor Mammedov <imammedo@redhat.com>
Message-Id: <20210121161504.1007247-1-imammedo@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
32-bit targets by definition do not support long mode; therefore, the
bit must be masked in the features supported by the accelerator.
As a side effect, this avoids setting up the 0x80000008 CPUID leaf
for
qemu-system-i386 -cpu host
which since commit 5a140b255d ("x86/cpu: Use max host physical address
if -cpu max option is applied") would have printed this error:
qemu-system-i386: phys-bits should be between 32 and 36 (but is 48)
Reported-by: Nathan Chancellor <natechancellor@gmail.com>
Tested-by: Nathan Chancellor <natechancellor@gmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
virtio-9p devices are often used to expose a virtual-filesystem to the
guest. There have been some bugs reported in this device, such as
CVE-2018-19364, and CVE-2021-20181. We should fuzz this device
This patch adds two virtio-9p configurations:
* One with the widely used -fsdev local driver. This driver leaks some
state in the form of files/directories created in the shared dir.
* One with the synth driver. While it is not used in the real world, this
driver won't leak leak state between fuzz inputs.
Signed-off-by: Alexander Bulekov <alxndr@bu.edu>
Reviewed-by: Darren Kenny <darren.kenny@oracle.com>
Message-Id: <20210117230924.449676-4-alxndr@bu.edu>
Signed-off-by: Alexander Bulekov <alxndr@bu.edu>
Reviewed-by: Darren Kenny <darren.kenny@oracle.com>
Message-Id: <20210117230924.449676-3-alxndr@bu.edu>
For some device configurations, it is useful to configure some
resources, and adjust QEMU arguments at runtime, prior to fuzzing. This
patch adds an "argfunc" to generic the generic_fuzz_config. When
specified, it is responsible for configuring the resources and returning
a string containing the corresponding QEMU arguments. This can be useful
for targets that rely on e.g.:
* a temporary qcow2 image
* a temporary directory
* an unused TCP port used to bind the VNC server
Signed-off-by: Alexander Bulekov <alxndr@bu.edu>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Message-Id: <20210117230924.449676-2-alxndr@bu.edu>
This is useful for building reproducers. Instead checking the code or
the QEMU_FUZZ_ARGS, the arguments are at the top of the crash log.
Signed-off-by: Alexander Bulekov <alxndr@bu.edu>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Message-Id: <20210117201014.271610-3-alxndr@bu.edu>
Disks work differently depending on the x86 machine type (SATA vs PATA).
Additionally, we should fuzz the atapi code paths, which might contain
vulnerabilities such as CVE-2020-29443. This patch adds hard-disk and
cdrom generic-fuzzer configs for both the pc (PATA) and q35 (SATA)
machine types.
Signed-off-by: Alexander Bulekov <alxndr@bu.edu>
Acked-by: Thomas Huth <thuth@redhat.com>
Reviewed-by: Darren Kenny <darren.kenny@oracle.com>
Message-Id: <20210120152211.109782-1-alxndr@bu.edu>
We passed an is_write flag to the fuzz_dma_read_cb function to
differentiate between the mapped DMA regions that need to be populated
with fuzzed data, and those that don't. We simply passed through the
address_space_map is_write parameter. The goal was to cut down on
unnecessarily populating mapped DMA regions, when they are not read
from.
Unfortunately, nothing precludes code from reading from regions mapped
with is_write=true. For example, see:
https://lists.gnu.org/archive/html/qemu-devel/2021-01/msg04729.html
This patch removes the is_write parameter to fuzz_dma_read_cb. As a
result, we will fill all mapped DMA regions with fuzzed data, ignoring
the specified transfer direction.
Signed-off-by: Alexander Bulekov <alxndr@bu.edu>
Reviewed-by: Darren Kenny <darren.kenny@oracle.com>
Message-Id: <20210120060255.558535-1-alxndr@bu.edu>
A number of hardware platforms are implementing mechanisms whereby the
hypervisor does not have unfettered access to guest memory, in order
to mitigate the security impact of a compromised hypervisor.
AMD's SEV implements this with in-cpu memory encryption, and Intel has
its own memory encryption mechanism. POWER has an upcoming mechanism
to accomplish this in a different way, using a new memory protection
level plus a small trusted ultravisor. s390 also has a protected
execution environment.
The current code (committed or draft) for these features has each
platform's version configured entirely differently. That doesn't seem
ideal for users, or particularly for management layers.
AMD SEV introduces a notionally generic machine option
"machine-encryption", but it doesn't actually cover any cases other
than SEV.
This series is a proposal to at least partially unify configuration
for these mechanisms, by renaming and generalizing AMD's
"memory-encryption" property. It is replaced by a
"confidential-guest-support" property pointing to a platform specific
object which configures and manages the specific details.
Note to Ram Pai: the documentation I've included for PEF is very
minimal. If you could send a patch expanding on that, it would be
very helpful.
Changes since v8:
* Rebase
* Fixed some cosmetic typos
Changes since v7:
* Tweaked and clarified meaning of the 'ready' flag
* Polished the interface to the PEF internals
* Shifted initialization for s390 PV later (I hope I've finally got
this after apply_cpu_model() where it needs to be)
Changes since v6:
* Moved to using OBJECT_DECLARE_TYPE and OBJECT_DEFINE_TYPE macros
* Assorted minor fixes
Changes since v5:
* Renamed from "securable guest memory" to "confidential guest
support"
* Simpler reworking of x86 boot time flash encryption
* Added a bunch of documentation
* Fixed some compile errors on POWER
Changes since v4:
* Renamed from "host trust limitation" to "securable guest memory",
which I think is marginally more descriptive
* Re-organized initialization, because the previous model called at
kvm_init didn't work for s390
* Assorted fixes to the s390 implementation; rudimentary testing
(gitlab CI) only
Changes since v3:
* Rebased
* Added first cut at handling of s390 protected virtualization
Changes since RFCv2:
* Rebased
* Removed preliminary SEV cleanups (they've been merged)
* Changed name to "host trust limitation"
* Added migration blocker to the PEF code (based on SEV's version)
Changes since RFCv1:
* Rebased
* Fixed some errors pointed out by Dave Gilbert
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Merge remote-tracking branch 'remotes/dg-gitlab/tags/cgs-pull-request' into staging
Generalize memory encryption models
A number of hardware platforms are implementing mechanisms whereby the
hypervisor does not have unfettered access to guest memory, in order
to mitigate the security impact of a compromised hypervisor.
AMD's SEV implements this with in-cpu memory encryption, and Intel has
its own memory encryption mechanism. POWER has an upcoming mechanism
to accomplish this in a different way, using a new memory protection
level plus a small trusted ultravisor. s390 also has a protected
execution environment.
The current code (committed or draft) for these features has each
platform's version configured entirely differently. That doesn't seem
ideal for users, or particularly for management layers.
AMD SEV introduces a notionally generic machine option
"machine-encryption", but it doesn't actually cover any cases other
than SEV.
This series is a proposal to at least partially unify configuration
for these mechanisms, by renaming and generalizing AMD's
"memory-encryption" property. It is replaced by a
"confidential-guest-support" property pointing to a platform specific
object which configures and manages the specific details.
Note to Ram Pai: the documentation I've included for PEF is very
minimal. If you could send a patch expanding on that, it would be
very helpful.
Changes since v8:
* Rebase
* Fixed some cosmetic typos
Changes since v7:
* Tweaked and clarified meaning of the 'ready' flag
* Polished the interface to the PEF internals
* Shifted initialization for s390 PV later (I hope I've finally got
this after apply_cpu_model() where it needs to be)
Changes since v6:
* Moved to using OBJECT_DECLARE_TYPE and OBJECT_DEFINE_TYPE macros
* Assorted minor fixes
Changes since v5:
* Renamed from "securable guest memory" to "confidential guest
support"
* Simpler reworking of x86 boot time flash encryption
* Added a bunch of documentation
* Fixed some compile errors on POWER
Changes since v4:
* Renamed from "host trust limitation" to "securable guest memory",
which I think is marginally more descriptive
* Re-organized initialization, because the previous model called at
kvm_init didn't work for s390
* Assorted fixes to the s390 implementation; rudimentary testing
(gitlab CI) only
Changes since v3:
* Rebased
* Added first cut at handling of s390 protected virtualization
Changes since RFCv2:
* Rebased
* Removed preliminary SEV cleanups (they've been merged)
* Changed name to "host trust limitation"
* Added migration blocker to the PEF code (based on SEV's version)
Changes since RFCv1:
* Rebased
* Fixed some errors pointed out by Dave Gilbert
# gpg: Signature made Mon 08 Feb 2021 06:07:27 GMT
# gpg: using RSA key 75F46586AE61A66CC44E87DC6C38CACA20D9B392
# gpg: Good signature from "David Gibson <david@gibson.dropbear.id.au>" [full]
# gpg: aka "David Gibson (Red Hat) <dgibson@redhat.com>" [full]
# gpg: aka "David Gibson (ozlabs.org) <dgibson@ozlabs.org>" [full]
# gpg: aka "David Gibson (kernel.org) <dwg@kernel.org>" [unknown]
# Primary key fingerprint: 75F4 6586 AE61 A66C C44E 87DC 6C38 CACA 20D9 B392
* remotes/dg-gitlab/tags/cgs-pull-request:
s390: Recognize confidential-guest-support option
confidential guest support: Alter virtio default properties for protected guests
spapr: PEF: prevent migration
spapr: Add PEF based confidential guest support
confidential guest support: Update documentation
confidential guest support: Move SEV initialization into arch specific code
confidential guest support: Introduce cgs "ready" flag
sev: Add Error ** to sev_kvm_init()
confidential guest support: Rework the "memory-encryption" property
confidential guest support: Move side effect out of machine_set_memory_encryption()
sev: Remove false abstraction of flash encryption
confidential guest support: Introduce new confidential guest support class
qom: Allow optional sugar props
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
At least some s390 cpu models support "Protected Virtualization" (PV),
a mechanism to protect guests from eavesdropping by a compromised
hypervisor.
This is similar in function to other mechanisms like AMD's SEV and
POWER's PEF, which are controlled by the "confidential-guest-support"
machine option. s390 is a slightly special case, because we already
supported PV, simply by using a CPU model with the required feature
(S390_FEAT_UNPACK).
To integrate this with the option used by other platforms, we
implement the following compromise:
- When the confidential-guest-support option is set, s390 will
recognize it, verify that the CPU can support PV (failing if not)
and set virtio default options necessary for encrypted or protected
guests, as on other platforms. i.e. if confidential-guest-support
is set, we will either create a guest capable of entering PV mode,
or fail outright.
- If confidential-guest-support is not set, guests might still be
able to enter PV mode, if the CPU has the right model. This may be
a little surprising, but shouldn't actually be harmful.
To start a guest supporting Protected Virtualization using the new
option use the command line arguments:
-object s390-pv-guest,id=pv0 -machine confidential-guest-support=pv0
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Tested-by: Christian Borntraeger <borntraeger@de.ibm.com>
Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com>
The default behaviour for virtio devices is not to use the platforms normal
DMA paths, but instead to use the fact that it's running in a hypervisor
to directly access guest memory. That doesn't work if the guest's memory
is protected from hypervisor access, such as with AMD's SEV or POWER's PEF.
So, if a confidential guest mechanism is enabled, then apply the
iommu_platform=on option so it will go through normal DMA mechanisms.
Those will presumably have some way of marking memory as shared with
the hypervisor or hardware so that DMA will work.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Reviewed-by: Greg Kurz <groug@kaod.org>
We haven't yet implemented the fairly involved handshaking that will be
needed to migrate PEF protected guests. For now, just use a migration
blocker so we get a meaningful error if someone attempts this (this is the
same approach used by AMD SEV).
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: Greg Kurz <groug@kaod.org>
Some upcoming POWER machines have a system called PEF (Protected
Execution Facility) which uses a small ultravisor to allow guests to
run in a way that they can't be eavesdropped by the hypervisor. The
effect is roughly similar to AMD SEV, although the mechanisms are
quite different.
Most of the work of this is done between the guest, KVM and the
ultravisor, with little need for involvement by qemu. However qemu
does need to tell KVM to allow secure VMs.
Because the availability of secure mode is a guest visible difference
which depends on having the right hardware and firmware, we don't
enable this by default. In order to run a secure guest you need to
create a "pef-guest" object and set the confidential-guest-support
property to point to it.
Note that this just *allows* secure guests, the architecture of PEF is
such that the guest still needs to talk to the ultravisor to enter
secure mode. Qemu has no direct way of knowing if the guest is in
secure mode, and certainly can't know until well after machine
creation time.
To start a PEF-capable guest, use the command line options:
-object pef-guest,id=pef0 -machine confidential-guest-support=pef0
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Reviewed-by: Greg Kurz <groug@kaod.org>
Now that we've implemented a generic machine option for configuring various
confidential guest support mechanisms:
1. Update docs/amd-memory-encryption.txt to reference this rather than
the earlier SEV specific option
2. Add a docs/confidential-guest-support.txt to cover the generalities of
the confidential guest support scheme
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Reviewed-by: Greg Kurz <groug@kaod.org>
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>
The platform specific details of mechanisms for implementing
confidential guest support may require setup at various points during
initialization. Thus, it's not really feasible to have a single cgs
initialization hook, but instead each mechanism needs its own
initialization calls in arch or machine specific code.
However, to make it harder to have a bug where a mechanism isn't
properly initialized under some circumstances, we want to have a
common place, late in boot, where we verify that cgs has been
initialized if it was requested.
This patch introduces a ready flag to the ConfidentialGuestSupport
base type to accomplish this, which we verify in
qemu_machine_creation_done().
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: Greg Kurz <groug@kaod.org>
This allows failures to be reported richly and idiomatically.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Currently the "memory-encryption" property is only looked at once we
get to kvm_init(). Although protection of guest memory from the
hypervisor isn't something that could really ever work with TCG, it's
not conceptually tied to the KVM accelerator.
In addition, the way the string property is resolved to an object is
almost identical to how a QOM link property is handled.
So, create a new "confidential-guest-support" link property which sets
this QOM interface link directly in the machine. For compatibility we
keep the "memory-encryption" property, but now implemented in terms of
the new property.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Reviewed-by: Greg Kurz <groug@kaod.org>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
When the "memory-encryption" property is set, we also disable KSM
merging for the guest, since it won't accomplish anything.
We want that, but doing it in the property set function itself is
thereoretically incorrect, in the unlikely event of some configuration
environment that set the property then cleared it again before
constructing the guest.
More importantly, it makes some other cleanups we want more difficult.
So, instead move this logic to machine_run_board_init() conditional on
the final value of the property.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Greg Kurz <groug@kaod.org>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
When AMD's SEV memory encryption is in use, flash memory banks (which are
initialed by pc_system_flash_map()) need to be encrypted with the guest's
key, so that the guest can read them.
That's abstracted via the kvm_memcrypt_encrypt_data() callback in the KVM
state.. except, that it doesn't really abstract much at all.
For starters, the only call site is in code specific to the 'pc'
family of machine types, so it's obviously specific to those and to
x86 to begin with. But it makes a bunch of further assumptions that
need not be true about an arbitrary confidential guest system based on
memory encryption, let alone one based on other mechanisms:
* it assumes that the flash memory is defined to be encrypted with the
guest key, rather than being shared with hypervisor
* it assumes that that hypervisor has some mechanism to encrypt data into
the guest, even though it can't decrypt it out, since that's the whole
point
* the interface assumes that this encrypt can be done in place, which
implies that the hypervisor can write into a confidential guests's
memory, even if what it writes isn't meaningful
So really, this "abstraction" is actually pretty specific to the way SEV
works. So, this patch removes it and instead has the PC flash
initialization code call into a SEV specific callback.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Several architectures have mechanisms which are designed to protect
guest memory from interference or eavesdropping by a compromised
hypervisor. AMD SEV does this with in-chip memory encryption and
Intel's TDX can do similar things. POWER's Protected Execution
Framework (PEF) accomplishes a similar goal using an ultravisor and
new memory protection features, instead of encryption.
To (partially) unify handling for these, this introduces a new
ConfidentialGuestSupport QOM base class. "Confidential" is kind of vague,
but "confidential computing" seems to be the buzzword about these schemes,
and "secure" or "protected" are often used in connection to unrelated
things (such as hypervisor-from-guest or guest-from-guest security).
The "support" in the name is significant because in at least some of the
cases it requires the guest to take specific actions in order to protect
itself from hypervisor eavesdropping.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
