History log of /qemu/hw/i386/kvm/xen_evtchn.c (Results 1 – 25 of 86)
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Revision tags: v9.0.0-rc2
# 95a36455 29-Mar-2024 Artem Chernyshev <artem.chernyshev@red-soft.ru>

hw/xen_evtchn: Initialize flush_kvm_routes

In xen_evtchn_soft_reset() variable flush_kvm_routes can
be used before being initialized.

Found by Linux Verification Center (linuxtesting.org) with SVAC

hw/xen_evtchn: Initialize flush_kvm_routes

In xen_evtchn_soft_reset() variable flush_kvm_routes can
be used before being initialized.

Found by Linux Verification Center (linuxtesting.org) with SVACE.

Signed-off-by: Oleg Sviridov <oleg.sviridov@red-soft.ru>
Signed-off-by: Artem Chernyshev <artem.chernyshev@red-soft.ru>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Message-ID: <20240329113939.257033-1-artem.chernyshev@red-soft.ru>
Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>

show more ...


Revision tags: v9.0.0-rc1, v9.0.0-rc0, v8.2.2, v7.2.10
# b54a9d46 24-Feb-2024 Bernhard Beschow <shentey@gmail.com>

hw/i386/pc: Rename "bus" attribute to "pcibus"

The attribute is of type PCIBus; reflect that in the name. It will also make the
next change more intuitive.

Suggested-by: Philippe Mathieu-Daudé <phi

hw/i386/pc: Rename "bus" attribute to "pcibus"

The attribute is of type PCIBus; reflect that in the name. It will also make the
next change more intuitive.

Suggested-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Signed-off-by: Bernhard Beschow <shentey@gmail.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Zhao Liu <zhao1.liu@intel.com>
Message-ID: <20240224135851.100361-3-shentey@gmail.com>
Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>

show more ...


Revision tags: v8.2.1, v8.1.5, v7.2.9
# 32ead8e6 02-Jan-2024 Stefan Hajnoczi <stefanha@redhat.com>

qemu/main-loop: rename QEMU_IOTHREAD_LOCK_GUARD to BQL_LOCK_GUARD

The name "iothread" is overloaded. Use the term Big QEMU Lock (BQL)
instead, it is already widely used and unambiguous.

Signed-off-

qemu/main-loop: rename QEMU_IOTHREAD_LOCK_GUARD to BQL_LOCK_GUARD

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>

show more ...


# 195801d7 02-Jan-2024 Stefan Hajnoczi <stefanha@redhat.com>

system/cpus: rename qemu_mutex_lock_iothread() to bql_lock()

The Big QEMU Lock (BQL) has many names and they are confusing. The
actual QemuMutex variable is called qemu_global_mutex but it's commonl

system/cpus: rename qemu_mutex_lock_iothread() to bql_lock()

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>

show more ...


Revision tags: v8.1.4, v7.2.8
# 9231a017 21-Dec-2023 Richard Henderson <richard.henderson@linaro.org>

hw/i386: Constify VMState

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Zhao Liu <zhao1.liu@intel.com>
Message-Id: <20231221031652.119827-32-richard.henderson@linaro.o

hw/i386: Constify VMState

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Zhao Liu <zhao1.liu@intel.com>
Message-Id: <20231221031652.119827-32-richard.henderson@linaro.org>

show more ...


Revision tags: v8.2.0, v8.2.0-rc4, v8.2.0-rc3, v8.2.0-rc2, v8.2.0-rc1, v7.2.7, v8.1.3, v8.2.0-rc0, v8.1.2, v8.1.1, v7.2.6, v8.0.5, v8.1.0, v8.1.0-rc4, v8.1.0-rc3, v7.2.5, v8.0.4
# be155098 02-Aug-2023 David Woodhouse <dwmw@amazon.co.uk>

hw/xen: Clean up event channel 'type_val' handling to use union

A previous implementation of this stuff used a 64-bit field for all of
the port information (vcpu/type/type_val) and did atomic exchan

hw/xen: Clean up event channel 'type_val' handling to use union

A previous implementation of this stuff used a 64-bit field for all of
the port information (vcpu/type/type_val) and did atomic exchanges on
them. When I implemented that in Qemu I regretted my life choices and
just kept it simple with locking instead.

So there's no need for the XenEvtchnPort to be so simplistic. We can
use a union for the pirq/virq/interdomain information, which lets us
keep a separate bit for the 'remote domain' in interdomain ports. A
single bit is enough since the only possible targets are loopback or
qemu itself.

So now we can ditch PORT_INFO_TYPEVAL_REMOTE_QEMU and the horrid
manual masking, although the in-memory representation is identical
so there's no change in the saved state ABI.

Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Reviewed-by: Paul Durrant <paul@xen.org>

show more ...


Revision tags: v8.2.0, v8.2.0-rc4, v8.2.0-rc3, v8.2.0-rc2, v8.2.0-rc1, v7.2.7, v8.1.3, v8.2.0-rc0, v8.1.2, v8.1.1, v7.2.6, v8.0.5, v8.1.0, v8.1.0-rc4, v8.1.0-rc3, v7.2.5, v8.0.4
# be155098 02-Aug-2023 David Woodhouse <dwmw@amazon.co.uk>

hw/xen: Clean up event channel 'type_val' handling to use union

A previous implementation of this stuff used a 64-bit field for all of
the port information (vcpu/type/type_val) and did atomic exchan

hw/xen: Clean up event channel 'type_val' handling to use union

A previous implementation of this stuff used a 64-bit field for all of
the port information (vcpu/type/type_val) and did atomic exchanges on
them. When I implemented that in Qemu I regretted my life choices and
just kept it simple with locking instead.

So there's no need for the XenEvtchnPort to be so simplistic. We can
use a union for the pirq/virq/interdomain information, which lets us
keep a separate bit for the 'remote domain' in interdomain ports. A
single bit is enough since the only possible targets are loopback or
qemu itself.

So now we can ditch PORT_INFO_TYPEVAL_REMOTE_QEMU and the horrid
manual masking, although the in-memory representation is identical
so there's no change in the saved state ABI.

Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Reviewed-by: Paul Durrant <paul@xen.org>

show more ...


# debc995e 24-Oct-2023 David Woodhouse <dwmw@amazon.co.uk>

hw/xen: take iothread mutex in xen_evtchn_reset_op()

The xen_evtchn_soft_reset() function requires the iothread mutex, but is
also called for the EVTCHNOP_reset hypercall. Ensure the mutex is taken

hw/xen: take iothread mutex in xen_evtchn_reset_op()

The xen_evtchn_soft_reset() function requires the iothread mutex, but is
also called for the EVTCHNOP_reset hypercall. Ensure the mutex is taken
in that case.

Cc: qemu-stable@nongnu.org
Fixes: a15b10978fe6 ("hw/xen: Implement EVTCHNOP_reset")
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Reviewed-by: Paul Durrant <paul@xen.org>

show more ...


# 18e83f28 11-Oct-2023 David Woodhouse <dwmw@amazon.co.uk>

hw/xen: select kernel mode for per-vCPU event channel upcall vector

A guest which has configured the per-vCPU upcall vector may set the
HVM_PARAM_CALLBACK_IRQ param to fairly much anything other tha

hw/xen: select kernel mode for per-vCPU event channel upcall vector

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: 91cce756179 ("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>

show more ...


# debc995e 24-Oct-2023 David Woodhouse <dwmw@amazon.co.uk>

hw/xen: take iothread mutex in xen_evtchn_reset_op()

The xen_evtchn_soft_reset() function requires the iothread mutex, but is
also called for the EVTCHNOP_reset hypercall. Ensure the mutex is taken

hw/xen: take iothread mutex in xen_evtchn_reset_op()

The xen_evtchn_soft_reset() function requires the iothread mutex, but is
also called for the EVTCHNOP_reset hypercall. Ensure the mutex is taken
in that case.

Cc: qemu-stable@nongnu.org
Fixes: a15b10978fe6 ("hw/xen: Implement EVTCHNOP_reset")
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Reviewed-by: Paul Durrant <paul@xen.org>

show more ...


# 18e83f28 11-Oct-2023 David Woodhouse <dwmw@amazon.co.uk>

hw/xen: select kernel mode for per-vCPU event channel upcall vector

A guest which has configured the per-vCPU upcall vector may set the
HVM_PARAM_CALLBACK_IRQ param to fairly much anything other tha

hw/xen: select kernel mode for per-vCPU event channel upcall vector

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: 91cce756179 ("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>

show more ...


Revision tags: v8.1.0-rc2, v8.1.0-rc1
# 75a87af9 25-Jul-2023 David Woodhouse <dwmw@amazon.co.uk>

hw/xen: prevent guest from binding loopback event channel to itself

Fuzzing showed that a guest could bind an interdomain port to itself, by
guessing the next port to be allocated and putting that a

hw/xen: prevent guest from binding loopback event channel to itself

Fuzzing showed that a guest could bind an interdomain port to itself, by
guessing the next port to be allocated and putting that as the 'remote'
port number. By chance, that works because the newly-allocated port has
type EVTCHNSTAT_unbound. It shouldn't.

Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Reviewed-by: Paul Durrant <paul@xen.org>
Message-Id: <20230801175747.145906-4-dwmw2@infradead.org>
Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>

show more ...


Revision tags: v8.1.0-rc0, v8.0.3, v7.2.4, v8.0.2, v8.0.1, v7.2.3, v7.2.2, v8.0.0, v8.0.0-rc4
# cf885b19 07-Apr-2023 David Woodhouse <dwmw@amazon.co.uk>

hw/xen: fix off-by-one in xen_evtchn_set_gsi()

Coverity points out (CID 1508128) a bounds checking error. We need to check
for gsi >= IOAPIC_NUM_PINS, not just greater-than.

Also fix up an assert()

hw/xen: fix off-by-one in xen_evtchn_set_gsi()

Coverity points out (CID 1508128) a bounds checking error. We need to check
for gsi >= IOAPIC_NUM_PINS, not just greater-than.

Also fix up an assert() that has the same problem, that Coverity didn't see.

Fixes: 4f81baa33ed6 ("hw/xen: Support GSI mapping to PIRQ")
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Message-Id: <20230801175747.145906-2-dwmw2@infradead.org>
Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>

show more ...


# eeedfe6c 12-Apr-2023 David Woodhouse <dwmw@amazon.co.uk>

hw/xen: Simplify emulated Xen platform init

I initially put the basic platform init (overlay pages, grant tables,
event channels) into mc->kvm_type because that was the earliest place
that could sen

hw/xen: Simplify emulated Xen platform init

I initially put the basic platform init (overlay pages, grant tables,
event channels) into mc->kvm_type because that was the earliest place
that could sensibly test for xen_mode==XEN_EMULATE.

The intent was to do this early enough that we could then initialise the
XenBus and other parts which would have depended on them, from a generic
location for both Xen and KVM/Xen in the PC-specific code, as seen in
https://lore.kernel.org/qemu-devel/20230116221919.1124201-16-dwmw2@infradead.org/

However, then the Xen on Arm patches came along, and *they* wanted to
do the XenBus init from a 'generic' Xen-specific location instead:
https://lore.kernel.org/qemu-devel/20230210222729.957168-4-sstabellini@kernel.org/

Since there's no generic location that covers all three, I conceded to
do it for XEN_EMULATE mode in pc_basic_devices_init().

And now there's absolutely no point in having some of the platform init
done from pc_machine_kvm_type(); we can move it all up to live in a
single place in pc_basic_devices_init(). This has the added benefit that
we can drop the separate xen_evtchn_connect_gsis() function completely,
and pass just the system GSIs in directly to xen_evtchn_create().

While I'm at it, it does no harm to explicitly pass in the *number* of
said GSIs, because it does make me twitch a bit to pass an array of
impicit size. During the lifetime of the KVM/Xen patchset, that had
already changed (albeit just cosmetically) from GSI_NUM_PINS to
IOAPIC_NUM_PINS.

And document a bit better that this is for the *output* GSI for raising
CPU0's events when the per-CPU vector isn't available. The fact that
we create a whole set of them and then only waggle the one we're told
to, instead of having a single output and only *connecting* it to the
GSI that it should be connected to, is still non-intuitive for me.

Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Reviewed-by: Paul Durrant <paul@xen.org>
Message-Id: <20230412185102.441523-2-dwmw2@infradead.org>
Signed-off-by: Anthony PERARD <anthony.perard@citrix.com>

show more ...


# eeedfe6c 12-Apr-2023 David Woodhouse <dwmw@amazon.co.uk>

hw/xen: Simplify emulated Xen platform init

I initially put the basic platform init (overlay pages, grant tables,
event channels) into mc->kvm_type because that was the earliest place
that could sen

hw/xen: Simplify emulated Xen platform init

I initially put the basic platform init (overlay pages, grant tables,
event channels) into mc->kvm_type because that was the earliest place
that could sensibly test for xen_mode==XEN_EMULATE.

The intent was to do this early enough that we could then initialise the
XenBus and other parts which would have depended on them, from a generic
location for both Xen and KVM/Xen in the PC-specific code, as seen in
https://lore.kernel.org/qemu-devel/20230116221919.1124201-16-dwmw2@infradead.org/

However, then the Xen on Arm patches came along, and *they* wanted to
do the XenBus init from a 'generic' Xen-specific location instead:
https://lore.kernel.org/qemu-devel/20230210222729.957168-4-sstabellini@kernel.org/

Since there's no generic location that covers all three, I conceded to
do it for XEN_EMULATE mode in pc_basic_devices_init().

And now there's absolutely no point in having some of the platform init
done from pc_machine_kvm_type(); we can move it all up to live in a
single place in pc_basic_devices_init(). This has the added benefit that
we can drop the separate xen_evtchn_connect_gsis() function completely,
and pass just the system GSIs in directly to xen_evtchn_create().

While I'm at it, it does no harm to explicitly pass in the *number* of
said GSIs, because it does make me twitch a bit to pass an array of
impicit size. During the lifetime of the KVM/Xen patchset, that had
already changed (albeit just cosmetically) from GSI_NUM_PINS to
IOAPIC_NUM_PINS.

And document a bit better that this is for the *output* GSI for raising
CPU0's events when the per-CPU vector isn't available. The fact that
we create a whole set of them and then only waggle the one we're told
to, instead of having a single output and only *connecting* it to the
GSI that it should be connected to, is still non-intuitive for me.

Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Reviewed-by: Paul Durrant <paul@xen.org>
Message-Id: <20230412185102.441523-2-dwmw2@infradead.org>
Signed-off-by: Anthony PERARD <anthony.perard@citrix.com>

show more ...


Revision tags: v8.0.0-rc3, v7.2.1, v8.0.0-rc2, v8.0.0-rc1
# cc37d98b 15-Mar-2023 Richard Henderson <richard.henderson@linaro.org>

*: Add missing includes of qemu/error-report.h

This had been pulled in via qemu/plugin.h from hw/core/cpu.h,
but that will be removed.

Signed-off-by: Richard Henderson <richard.henderson@linaro.org

*: Add missing includes of qemu/error-report.h

This had been pulled in via qemu/plugin.h from hw/core/cpu.h,
but that will be removed.

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Message-Id: <20230310195252.210956-5-richard.henderson@linaro.org>
[AJB: add various additional cases shown by CI]
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <20230315174331.2959-15-alex.bennee@linaro.org>
Reviewed-by: Emilio Cota <cota@braap.org>

show more ...


Revision tags: v8.0.0-rc0
# 4dfd5fb1 01-Jan-2023 David Woodhouse <dwmw@amazon.co.uk>

hw/xen: Hook up emulated implementation for event channel operations

We provided the backend-facing evtchn functions very early on as part of
the core Xen platform support, since things like timers

hw/xen: Hook up emulated implementation for event channel operations

We provided the backend-facing evtchn functions very early on as part of
the core Xen platform support, since things like timers and xenstore need
to use them.

By what may or may not be an astonishing coincidence, those functions
just *happen* all to have exactly the right function prototypes to slot
into the evtchn_backend_ops table and be called by the PV backends.

Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Reviewed-by: Paul Durrant <paul@xen.org>

show more ...


Revision tags: v8.0.0-rc0
# 4dfd5fb1 01-Jan-2023 David Woodhouse <dwmw@amazon.co.uk>

hw/xen: Hook up emulated implementation for event channel operations

We provided the backend-facing evtchn functions very early on as part of
the core Xen platform support, since things like timers

hw/xen: Hook up emulated implementation for event channel operations

We provided the backend-facing evtchn functions very early on as part of
the core Xen platform support, since things like timers and xenstore need
to use them.

By what may or may not be an astonishing coincidence, those functions
just *happen* all to have exactly the right function prototypes to slot
into the evtchn_backend_ops table and be called by the PV backends.

Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Reviewed-by: Paul Durrant <paul@xen.org>

show more ...


Revision tags: v8.0.0-rc0
# 4dfd5fb1 01-Jan-2023 David Woodhouse <dwmw@amazon.co.uk>

hw/xen: Hook up emulated implementation for event channel operations

We provided the backend-facing evtchn functions very early on as part of
the core Xen platform support, since things like timers

hw/xen: Hook up emulated implementation for event channel operations

We provided the backend-facing evtchn functions very early on as part of
the core Xen platform support, since things like timers and xenstore need
to use them.

By what may or may not be an astonishing coincidence, those functions
just *happen* all to have exactly the right function prototypes to slot
into the evtchn_backend_ops table and be called by the PV backends.

Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Reviewed-by: Paul Durrant <paul@xen.org>

show more ...


Revision tags: v8.0.0-rc0
# 4dfd5fb1 01-Jan-2023 David Woodhouse <dwmw@amazon.co.uk>

hw/xen: Hook up emulated implementation for event channel operations

We provided the backend-facing evtchn functions very early on as part of
the core Xen platform support, since things like timers

hw/xen: Hook up emulated implementation for event channel operations

We provided the backend-facing evtchn functions very early on as part of
the core Xen platform support, since things like timers and xenstore need
to use them.

By what may or may not be an astonishing coincidence, those functions
just *happen* all to have exactly the right function prototypes to slot
into the evtchn_backend_ops table and be called by the PV backends.

Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Reviewed-by: Paul Durrant <paul@xen.org>

show more ...


# e16aff4c 18-Jan-2023 David Woodhouse <dwmw@amazon.co.uk>

kvm/i386: Add xen-evtchn-max-pirq property

The default number of PIRQs is set to 256 to avoid issues with 32-bit MSI
devices. Allow it to be increased if the user desires.

Signed-off-by: David Wood

kvm/i386: Add xen-evtchn-max-pirq property

The default number of PIRQs is set to 256 to avoid issues with 32-bit MSI
devices. Allow it to be increased if the user desires.

Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Reviewed-by: Paul Durrant <paul@xen.org>

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# 6096cf78 13-Jan-2023 David Woodhouse <dwmw@amazon.co.uk>

hw/xen: Support MSI mapping to PIRQ

The way that Xen handles MSI PIRQs is kind of awful.

There is a special MSI message which targets a PIRQ. The vector in the
low bits of data must be zero. The lo

hw/xen: Support MSI mapping to PIRQ

The way that Xen handles MSI PIRQs is kind of awful.

There is a special MSI message which targets a PIRQ. The vector in the
low bits of data must be zero. The low 8 bits of the PIRQ# are in the
destination ID field, the extended destination ID field is unused, and
instead the high bits of the PIRQ# are in the high 32 bits of the address.

Using the high bits of the address means that we can't intercept and
translate these messages in kvm_send_msi(), because they won't be caught
by the APIC — addresses like 0x1000fee46000 aren't in the APIC's range.

So we catch them in pci_msi_trigger() instead, and deliver the event
channel directly.

That isn't even the worst part. The worst part is that Xen snoops on
writes to devices' MSI vectors while they are *masked*. When a MSI
message is written which looks like it targets a PIRQ, it remembers
the device and vector for later.

When the guest makes a hypercall to bind that PIRQ# (snooped from a
marked MSI vector) to an event channel port, Xen *unmasks* that MSI
vector on the device. Xen guests using PIRQ delivery of MSI don't
ever actually unmask the MSI for themselves.

Now that this is working we can finally enable XENFEAT_hvm_pirqs and
let the guest use it all.

Tested with passthrough igb and emulated e1000e + AHCI.

CPU0 CPU1
0: 65 0 IO-APIC 2-edge timer
1: 0 14 xen-pirq 1-ioapic-edge i8042
4: 0 846 xen-pirq 4-ioapic-edge ttyS0
8: 1 0 xen-pirq 8-ioapic-edge rtc0
9: 0 0 xen-pirq 9-ioapic-level acpi
12: 257 0 xen-pirq 12-ioapic-edge i8042
24: 9600 0 xen-percpu -virq timer0
25: 2758 0 xen-percpu -ipi resched0
26: 0 0 xen-percpu -ipi callfunc0
27: 0 0 xen-percpu -virq debug0
28: 1526 0 xen-percpu -ipi callfuncsingle0
29: 0 0 xen-percpu -ipi spinlock0
30: 0 8608 xen-percpu -virq timer1
31: 0 874 xen-percpu -ipi resched1
32: 0 0 xen-percpu -ipi callfunc1
33: 0 0 xen-percpu -virq debug1
34: 0 1617 xen-percpu -ipi callfuncsingle1
35: 0 0 xen-percpu -ipi spinlock1
36: 8 0 xen-dyn -event xenbus
37: 0 6046 xen-pirq -msi ahci[0000:00:03.0]
38: 1 0 xen-pirq -msi-x ens4
39: 0 73 xen-pirq -msi-x ens4-rx-0
40: 14 0 xen-pirq -msi-x ens4-rx-1
41: 0 32 xen-pirq -msi-x ens4-tx-0
42: 47 0 xen-pirq -msi-x ens4-tx-1

Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Reviewed-by: Paul Durrant <paul@xen.org>

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# 4f81baa3 13-Jan-2023 David Woodhouse <dwmw@amazon.co.uk>

hw/xen: Support GSI mapping to PIRQ

If I advertise XENFEAT_hvm_pirqs then a guest now boots successfully as
long as I tell it 'pci=nomsi'.

[root@localhost ~]# cat /proc/interrupts
CPU0

hw/xen: Support GSI mapping to PIRQ

If I advertise XENFEAT_hvm_pirqs then a guest now boots successfully as
long as I tell it 'pci=nomsi'.

[root@localhost ~]# cat /proc/interrupts
CPU0
0: 52 IO-APIC 2-edge timer
1: 16 xen-pirq 1-ioapic-edge i8042
4: 1534 xen-pirq 4-ioapic-edge ttyS0
8: 1 xen-pirq 8-ioapic-edge rtc0
9: 0 xen-pirq 9-ioapic-level acpi
11: 5648 xen-pirq 11-ioapic-level ahci[0000:00:04.0]
12: 257 xen-pirq 12-ioapic-edge i8042
...

Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Reviewed-by: Paul Durrant <paul@xen.org>

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# aa98ee38 13-Jan-2023 David Woodhouse <dwmw@amazon.co.uk>

hw/xen: Implement emulated PIRQ hypercall support

This wires up the basic infrastructure but the actual interrupts aren't
there yet, so don't advertise it to the guest.

Signed-off-by: David Woodhou

hw/xen: Implement emulated PIRQ hypercall support

This wires up the basic infrastructure but the actual interrupts aren't
there yet, so don't advertise it to the guest.

Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Reviewed-by: Paul Durrant <paul@xen.org>

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# 799c2354 13-Jan-2023 David Woodhouse <dwmw@amazon.co.uk>

i386/xen: Implement HYPERVISOR_physdev_op

Just hook up the basic hypercalls to stubs in xen_evtchn.c for now.

Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Reviewed-by: Paul Durrant <paul@xen.

i386/xen: Implement HYPERVISOR_physdev_op

Just hook up the basic hypercalls to stubs in xen_evtchn.c for now.

Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Reviewed-by: Paul Durrant <paul@xen.org>

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