Implement support for the KVM_X86_SEV_VM and KVM_X86_SEV_ES_VM virtual
machine types, and the KVM_SEV_INIT2 function of KVM_MEMORY_ENCRYPT_OP.
These replace the KVM_SEV_INIT and KVM_SEV_ES_INIT functions, and have
several advantages:
- sharing the initialization sequence with SEV-SNP and TDX
- allowing arguments including the set of desired VMSA features
- protection against invalid use of KVM_GET/SET_* ioctls for guests
with encrypted state
If the KVM_X86_SEV_VM and KVM_X86_SEV_ES_VM types are not supported,
fall back to KVM_SEV_INIT and KVM_SEV_ES_INIT (which use the
default x86 VM type).
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
KVM is introducing a new API to create confidential guests, which
will be used by TDX and SEV-SNP but is also available for SEV and
SEV-ES. The API uses the VM type argument to KVM_CREATE_VM to
identify which confidential computing technology to use.
Since there are no other expected uses of VM types, delegate
mc->kvm_type() for x86 boards to the confidential-guest-support
object pointed to by ms->cgs.
For example, if a sev-guest object is specified to confidential-guest-support,
like,
qemu -machine ...,confidential-guest-support=sev0 \
-object sev-guest,id=sev0,...
it will check if a VM type KVM_X86_SEV_VM or KVM_X86_SEV_ES_VM
is supported, and if so use them together with the KVM_SEV_INIT2
function of the KVM_MEMORY_ENCRYPT_OP ioctl. If not, it will fall back to
KVM_SEV_INIT and KVM_SEV_ES_INIT.
This is a preparatory work towards TDX and SEV-SNP support, but it
will also enable support for VMSA features such as DebugSwap, which
are only available via KVM_SEV_INIT2.
Co-developed-by: Xiaoyao Li <xiaoyao.li@intel.com>
Signed-off-by: Xiaoyao Li <xiaoyao.li@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Board reset requires writing a fresh CPU state. As far as KVM is
concerned, the only thing that blocks reset is that CPU state is
encrypted; therefore, kvm_cpus_are_resettable() can simply check
if that is the case.
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Use confidential_guest_kvm_init() instead of calling SEV
specific sev_kvm_init(). This allows the introduction of multiple
confidential-guest-support subclasses for different x86 vendors.
As a bonus, stubs are not needed anymore since there is no
direct call from target/i386/kvm/kvm.c to SEV code.
Signed-off-by: Xiaoyao Li <xiaoyao.li@intel.com>
Message-Id: <20240229060038.606591-1-xiaoyao.li@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Move the architectural (for lack of a better term) CPUID leaf generation
to a separate helper so that the generation code can be reused by TDX,
which needs to generate a canonical VM-scoped configuration.
For now this is just a cleanup, so keep the function static.
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Xiaoyao Li <xiaoyao.li@intel.com>
Message-ID: <20240229063726.610065-23-xiaoyao.li@intel.com>
Reviewed-by: Xiaoyao Li <xiaoyao.li@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Query kvm for supported guest physical address bits, in cpuid
function 80000008, eax[23:16]. Usually this is identical to host
physical address bits. With NPT or EPT being used this might be
restricted to 48 (max 4-level paging address space size) even if
the host cpu supports more physical address bits.
When set pass this to the guest, using cpuid too. Guest firmware
can use this to figure how big the usable guest physical address
space is, so PCI bar mapping are actually reachable.
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Reviewed-by: Xiaoyao Li <xiaoyao.li@intel.com>
Reviewed-by: Zhao Liu <zhao1.liu@intel.com>
Message-ID: <20240318155336.156197-2-kraxel@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Some Windows versions crash at boot or fail to enable the VMBus device if
they don't see the expected set of Hyper-V features (enlightenments).
Since this provides poor user experience let's warn user if the VMBus
device is enabled without the recommended set of Hyper-V features.
The recommended set is the minimum set of Hyper-V features required to make
the VMBus device work properly in Windows Server versions 2016, 2019 and
2022.
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Maciej S. Szmigiero <maciej.szmigiero@oracle.com>
CPUID leaf 7 was grouped together with SGX leaf 0x12 by commit
b9edbadefb ("i386: Propagate SGX CPUID sub-leafs to KVM") by mistake.
SGX leaf 0x12 has its specific logic to check if subleaf (starting from 2)
is valid or not by checking the bit 0:3 of corresponding EAX is 1 or
not.
Leaf 7 follows the logic that EAX of subleaf 0 enumerates the maximum
valid subleaf.
Fixes: b9edbadefb ("i386: Propagate SGX CPUID sub-leafs to KVM")
Signed-off-by: Xiaoyao Li <xiaoyao.li@intel.com>
Message-ID: <20240125024016.2521244-4-xiaoyao.li@intel.com>
Cc: qemu-stable@nongnu.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
No such constraint that subleaf index needs to be less than 64.
Signed-off-by: Xiaoyao Li <xiaoyao.li@intel.com>
Reviewed-by:Yang Weijiang <weijiang.yang@intel.com>
Message-ID: <20240125024016.2521244-3-xiaoyao.li@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Existing code misses a decrement of cpuid_i when skip leaf 0x1F.
There's a blank CPUID entry(with leaf, subleaf as 0, and all fields
stuffed 0s) left in the CPUID array.
It conflicts with correct CPUID leaf 0.
Signed-off-by: Xiaoyao Li <xiaoyao.li@intel.com>
Reviewed-by:Yang Weijiang <weijiang.yang@intel.com>
Message-ID: <20240125024016.2521244-2-xiaoyao.li@intel.com>
Cc: qemu-stable@nongnu.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
The name "iothread" is overloaded. Use the term Big QEMU Lock (BQL)
instead, it is already widely used and unambiguous.
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Paul Durrant <paul@xen.org>
Acked-by: David Woodhouse <dwmw@amazon.co.uk>
Reviewed-by: Cédric Le Goater <clg@kaod.org>
Acked-by: Ilya Leoshkevich <iii@linux.ibm.com>
Reviewed-by: Harsh Prateek Bora <harshpb@linux.ibm.com>
Reviewed-by: Akihiko Odaki <akihiko.odaki@daynix.com>
Message-id: 20240102153529.486531-3-stefanha@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
The Big QEMU Lock (BQL) has many names and they are confusing. The
actual QemuMutex variable is called qemu_global_mutex but it's commonly
referred to as the BQL in discussions and some code comments. The
locking APIs, however, are called qemu_mutex_lock_iothread() and
qemu_mutex_unlock_iothread().
The "iothread" name is historic and comes from when the main thread was
split into into KVM vcpu threads and the "iothread" (now called the main
loop thread). I have contributed to the confusion myself by introducing
a separate --object iothread, a separate concept unrelated to the BQL.
The "iothread" name is no longer appropriate for the BQL. Rename the
locking APIs to:
- void bql_lock(void)
- void bql_unlock(void)
- bool bql_locked(void)
There are more APIs with "iothread" in their names. Subsequent patches
will rename them. There are also comments and documentation that will be
updated in later patches.
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Paul Durrant <paul@xen.org>
Acked-by: Fabiano Rosas <farosas@suse.de>
Acked-by: David Woodhouse <dwmw@amazon.co.uk>
Reviewed-by: Cédric Le Goater <clg@kaod.org>
Acked-by: Peter Xu <peterx@redhat.com>
Acked-by: Eric Farman <farman@linux.ibm.com>
Reviewed-by: Harsh Prateek Bora <harshpb@linux.ibm.com>
Acked-by: Hyman Huang <yong.huang@smartx.com>
Reviewed-by: Akihiko Odaki <akihiko.odaki@daynix.com>
Message-id: 20240102153529.486531-2-stefanha@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Commit 7191f24c7f ("accel/kvm/kvm-all: Handle register access errors")
added error checking for KVM_SET_SREGS/KVM_SET_SREGS2. In doing so, it
exposed a long-running bug in current KVM support for SEV-ES where the
kernel assumes that MSR_EFER_LMA will be set explicitly by the guest
kernel, in which case EFER write traps would result in KVM eventually
seeing MSR_EFER_LMA get set and recording it in such a way that it would
be subsequently visible when accessing it via KVM_GET_SREGS/etc.
However, guest kernels currently rely on MSR_EFER_LMA getting set
automatically when MSR_EFER_LME is set and paging is enabled via
CR0_PG_MASK. As a result, the EFER write traps don't actually expose the
MSR_EFER_LMA bit, even though it is set internally, and when QEMU
subsequently tries to pass this EFER value back to KVM via
KVM_SET_SREGS* it will fail various sanity checks and return -EINVAL,
which is now considered fatal due to the aforementioned QEMU commit.
This can be addressed by inferring the MSR_EFER_LMA bit being set when
paging is enabled and MSR_EFER_LME is set, and synthesizing it to ensure
the expected bits are all present in subsequent handling on the host
side.
Ultimately, this handling will be implemented in the host kernel, but to
avoid breaking QEMU's SEV-ES support when using older host kernels, the
same handling can be done in QEMU just after fetching the register
values via KVM_GET_SREGS*. Implement that here.
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Cc: Akihiko Odaki <akihiko.odaki@daynix.com>
Cc: Philippe Mathieu-Daudé <philmd@linaro.org>
Cc: Lara Lazier <laramglazier@gmail.com>
Cc: Vitaly Kuznetsov <vkuznets@redhat.com>
Cc: Maxim Levitsky <mlevitsk@redhat.com>
Cc: <kvm@vger.kernel.org>
Fixes: 7191f24c7f ("accel/kvm/kvm-all: Handle register access errors")
Signed-off-by: Michael Roth <michael.roth@amd.com>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-ID: <20231206155821.1194551-1-michael.roth@amd.com>
Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20230918160257.30127-4-philmd@linaro.org>
The primary console is special because the toolstack maps a page into
the guest for its ring, and also allocates the guest-side event channel.
The guest's grant table is even primed to export that page using a known
grant ref#. Add support for all that in emulated mode, so that we can
have a primary console.
For reasons unclear, the backends running under real Xen don't just use
a mapping of the well-known GNTTAB_RESERVED_CONSOLE grant ref (which
would also be in the ring-ref node in XenStore). Instead, the toolstack
sets the ring-ref node of the primary console to the GFN of the guest
page. The backend is expected to handle that special case and map it
with foreignmem operations instead.
We don't have an implementation of foreignmem ops for emulated Xen mode,
so just make it map GNTTAB_RESERVED_CONSOLE instead. This would probably
work for real Xen too, but we can't work out how to make real Xen create
a primary console of type "ioemu" to make QEMU drive it, so we can't
test that; might as well leave it as it is for now under Xen.
Now at last we can boot the Xen PV shim and run PV kernels in QEMU.
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Reviewed-by: Paul Durrant <paul@xen.org>
This will allow Linux guests (since v6.0) to use the per-vCPU upcall
vector delivered as MSI through the local APIC.
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Reviewed-by: Paul Durrant <paul@xen.org>
A guest which has configured the per-vCPU upcall vector may set the
HVM_PARAM_CALLBACK_IRQ param to fairly much anything other than zero.
For example, Linux v6.0+ after commit b1c3497e604 ("x86/xen: Add support
for HVMOP_set_evtchn_upcall_vector") will just do this after setting the
vector:
/* Trick toolstack to think we are enlightened. */
if (!cpu)
rc = xen_set_callback_via(1);
That's explicitly setting the delivery to GSI#1, but it's supposed to be
overridden by the per-vCPU vector setting. This mostly works in Qemu
*except* for the logic to enable the in-kernel handling of event channels,
which falsely determines that the kernel cannot accelerate GSI delivery
in this case.
Add a kvm_xen_has_vcpu_callback_vector() to report whether vCPU#0 has
the vector set, and use that in xen_evtchn_set_callback_param() to
enable the kernel acceleration features even when the param *appears*
to be set to target a GSI.
Preserve the Xen behaviour that when HVM_PARAM_CALLBACK_IRQ is set to
*zero* the event channel delivery is disabled completely. (Which is
what that bizarre guest behaviour is working round in the first place.)
Cc: qemu-stable@nongnu.org
Fixes: 91cce75617 ("hw/xen: Add xen_evtchn device for event channel emulation")
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Reviewed-by: Paul Durrant <paul@xen.org>
The per-vCPU upcall vector support had three problems. Firstly it was
using the wrong hypercall argument and would always return -EFAULT when
the guest tried to set it up. Secondly it was using the wrong ioctl() to
pass the vector to the kernel and thus the *kernel* would always return
-EINVAL. Finally, even when delivering the event directly from userspace
with an MSI, it put the destination CPU ID into the wrong bits of the
MSI address.
Linux doesn't (yet) use this mode so it went without decent testing
for a while.
Cc: qemu-stable@nongnu.org
Fixes: 105b47fdf2 ("i386/xen: implement HVMOP_set_evtchn_upcall_vector")
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Reviewed-by: Paul Durrant <paul@xen.org>
This confuses lscpu into thinking it's running in PVH mode.
Cc: qemu-stable@nongnu.org
Fixes: bedcc13924 ("i386/xen: implement HYPERVISOR_xen_version")
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Reviewed-by: Paul Durrant <paul@xen.org>
This was introduced in KVM in Linux 2.6.33, we can require it
unconditionally. KVM_CLOCK_TSC_STABLE was only added in Linux 4.9,
for now do not require it (though it would allow the removal of some
pretty yucky code).
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This was introduced in KVM in Linux 2.6.36, and could already be used at
the time to save/restore FPU data even on older processor. We can require
it unconditionally and stop using KVM_GET/SET_FPU.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This was introduced in KVM in Linux 3.5, we can require it unconditionally
in kvm_irqchip_send_msi(). However, not all architectures have to implement
it so check it only in x86, the only architecture that ever had MSI injection
but not KVM_CAP_SIGNAL_MSI.
ARM uses it to detect the presence of the ITS emulation in the kernel,
introduced in Linux 4.8. Assume that it's there and possibly fail when
realizing the arm-its-kvm device.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Modify migrate_add_blocker and migrate_del_blocker to take an Error **
reason. This allows migration to own the Error object, so that if
an error occurs in migrate_add_blocker, migration code can free the Error
and clear the client handle, simplifying client code. It also simplifies
the migrate_del_blocker call site.
In addition, this is a pre-requisite for a proposed future patch that would
add a mode argument to migration requests to support live update, and
maintain a list of blockers for each mode. A blocker may apply to a single
mode or to multiple modes, and passing Error** will allow one Error object
to be registered for multiple modes.
No functional change.
Signed-off-by: Steve Sistare <steven.sistare@oracle.com>
Tested-by: Michael Galaxy <mgalaxy@akamai.com>
Reviewed-by: Michael Galaxy <mgalaxy@akamai.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <1697634216-84215-1-git-send-email-steven.sistare@oracle.com>
When explicitly booting a multiple vcpus vm with "-cpu +ht", it gets
warning of
warning: host doesn't support requested feature: CPUID.01H:EDX.ht [bit 28]
Make CPUID_HT as supported unconditionally can resolve the warning.
However it introduces another issue that it also expose CPUID_HT to
guest when "-cpu host/max" with only 1 vcpu. To fix this, need mark
CPUID_HT as the no_autoenable_flags.
Signed-off-by: Xiaoyao Li <xiaoyao.li@intel.com>
Message-ID: <20231010060539.210258-1-xiaoyao.li@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Software MMU is TCG specific. Here 'softmmu' is misused
for system emulation. Anyhow, since KVM is system emulation
specific, just rename as 'i386_kvm_ss'.
Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Message-ID: <20231004090629.37473-10-philmd@linaro.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
accel_cpu_realize() is a generic function working with CPUs
from any target. Rename it using '_common_' to emphasis it is
not target specific.
Suggested-by: Claudio Fontana <cfontana@suse.de>
Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Message-Id: <20231003123026.99229-4-philmd@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
The AccelCPUClass::cpu_realizefn handler is meant for target
specific code, rename it using '_target_' to emphasis it.
Suggested-by: Claudio Fontana <cfontana@suse.de>
Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Message-Id: <20231003123026.99229-3-philmd@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
We use the '*fn' suffix for handlers, this is a public method.
Drop the suffix.
Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Claudio Fontana <cfontana@suse.de>
Message-Id: <20231003123026.99229-2-philmd@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
kvm_pc_setup_irq_routing() is only defined for x86 targets (in
hw/i386/kvm/apic.c). Its declaration is pointless on all
other targets.
Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Message-ID: <20230904124325.79040-14-philmd@linaro.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
kvm_has_pit_state2() is only defined for x86 targets (in
target/i386/kvm/kvm.c). Its declaration is pointless on
all other targets. Have it return a boolean.
Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Message-ID: <20230904124325.79040-13-philmd@linaro.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
kvm_get_apic_state() is only defined for x86 targets (in
hw/i386/kvm/apic.c). Its declaration is pointless on all
other targets.
Since we include "linux-headers/asm-x86/kvm.h", no need
to forward-declare 'struct kvm_lapic_state'.
Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Message-ID: <20230904124325.79040-12-philmd@linaro.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
kvm_arch_get_supported_cpuid() / kvm_arch_get_supported_msr_feature()
are only defined for x86 targets (in target/i386/kvm/kvm.c). Their
declarations are pointless on other targets.
Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Message-ID: <20230904124325.79040-11-philmd@linaro.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Keep the function accessed by target/i386/ and hw/i386/
exposed, restrict the ones accessed by target/i386/kvm/.
Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Message-ID: <20230904124325.79040-10-philmd@linaro.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Call kvm_enabled() before kvm_hv_vpindex_settable()
to let the compiler elide its call.
kvm-stub.c is now empty, remove it.
Suggested-by: Daniel Henrique Barboza <dbarboza@ventanamicro.com>
Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Message-ID: <20230904124325.79040-9-philmd@linaro.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Call kvm_enabled() before kvm_enable_x2apic() to let the compiler elide
its call. Cleanup the code by simplifying "!xen_enabled() &&
kvm_enabled()" to just "kvm_enabled()".
Suggested-by: Daniel Henrique Barboza <dbarboza@ventanamicro.com>
Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Message-ID: <20230904124325.79040-8-philmd@linaro.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
All these functions:
- kvm_arch_get_supported_cpuid()
- kvm_has_smm(()
- kvm_hyperv_expand_features()
- kvm_set_max_apic_id()
are called after checking for kvm_enabled(), which is
false when KVM is not built. Since the compiler elides
these functions, their stubs are not used and can be
removed.
Inspired-by: Daniel Henrique Barboza <dbarboza@ventanamicro.com>
Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Message-ID: <20230904124325.79040-7-philmd@linaro.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
In order to have cpu-sysemu.c become accelerator-agnostic,
inline kvm_apic_in_kernel() -- which is a simple wrapper
to kvm_irqchip_in_kernel() -- and use the generic "sysemu/kvm.h"
header.
Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Message-ID: <20230904124325.79040-6-philmd@linaro.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Changes the signature of the target-defined functions for
inserting/removing kvm hw breakpoints. The address and length arguments
are now of vaddr type, which both matches the type used internally in
accel/kvm/kvm-all.c and makes the api target-agnostic.
Signed-off-by: Anton Johansson <anjo@rev.ng>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20230807155706.9580-4-anjo@rev.ng>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
kvm_arch_get_default_type() returns the default KVM type. This hook is
particularly useful to derive a KVM type that is valid for "none"
machine model, which is used by libvirt to probe the availability of
KVM.
For MIPS, the existing mips_kvm_type() is reused. This function ensures
the availability of VZ which is mandatory to use KVM on the current
QEMU.
Cc: qemu-stable@nongnu.org
Signed-off-by: Akihiko Odaki <akihiko.odaki@daynix.com>
Message-id: 20230727073134.134102-2-akihiko.odaki@daynix.com
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
[PMM: added doc comment for new function]
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Coverity points out (CID 1507534, 1507968) that we sometimes access
env->xen_singleshot_timer_ns under the protection of
env->xen_timers_lock and sometimes not.
This isn't always an issue. There are two modes for the timers; if the
kernel supports the EVTCHN_SEND capability then it handles all the timer
hypercalls and delivery internally, and all we use the field for is to
get/set the timer as part of the vCPU state via an ioctl(). If the
kernel doesn't have that support, then we do all the emulation within
qemu, and *those* are the code paths where we actually care about the
locking.
But it doesn't hurt to be a little bit more consistent and avoid having
to explain *why* it's OK.
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Reviewed-by: Paul Durrant <paul@xen.org>
Message-Id: <20230801175747.145906-3-dwmw2@infradead.org>
Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
