* Re: [PATCH v2 08/12] KVM: arm64: Allow userspace to configure a vCPU's virtual offset
@ 2021-07-18 20:23 kernel test robot
0 siblings, 0 replies; 4+ messages in thread
From: kernel test robot @ 2021-07-18 20:23 UTC (permalink / raw)
To: kbuild
[-- Attachment #1: Type: text/plain, Size: 3679 bytes --]
CC: kbuild-all(a)lists.01.org
In-Reply-To: <20210716212629.2232756-9-oupton@google.com>
References: <20210716212629.2232756-9-oupton@google.com>
TO: Oliver Upton <oupton@google.com>
TO: kvm(a)vger.kernel.org
TO: kvmarm(a)lists.cs.columbia.edu
CC: Paolo Bonzini <pbonzini@redhat.com>
CC: Sean Christopherson <seanjc@google.com>
CC: Marc Zyngier <maz@kernel.org>
CC: Peter Shier <pshier@google.com>
CC: Jim Mattson <jmattson@google.com>
CC: David Matlack <dmatlack@google.com>
CC: Ricardo Koller <ricarkol@google.com>
CC: Jing Zhang <jingzhangos@google.com>
Hi Oliver,
Thank you for the patch! Perhaps something to improve:
[auto build test WARNING on kvm/queue]
[also build test WARNING on vhost/linux-next v5.14-rc1 next-20210716]
[cannot apply to kvmarm/next]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch]
url: https://github.com/0day-ci/linux/commits/Oliver-Upton/KVM-Add-idempotent-controls-for-migrating-system-counter-state/20210718-103407
base: https://git.kernel.org/pub/scm/virt/kvm/kvm.git queue
:::::: branch date: 18 hours ago
:::::: commit date: 18 hours ago
compiler: gcc-10 (Ubuntu 10.3.0-1ubuntu1~20.04) 10.3.0
reproduce:
cd tools/perf && ./check-headers.sh
If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>
perfheadercheck warnings: (new ones prefixed by >>)
Warning: Kernel ABI header at 'tools/arch/arm64/include/uapi/asm/kvm.h' differs from latest version at 'arch/arm64/include/uapi/asm/kvm.h': 187> struct kvm_arm_copy_mte_tags {
Warning: Kernel ABI header at 'tools/arch/arm64/include/uapi/asm/kvm.h' differs from latest version at 'arch/arm64/include/uapi/asm/kvm.h': 188> __u64 guest_ipa;
Warning: Kernel ABI header at 'tools/arch/arm64/include/uapi/asm/kvm.h' differs from latest version at 'arch/arm64/include/uapi/asm/kvm.h': 189> __u64 length;
Warning: Kernel ABI header at 'tools/arch/arm64/include/uapi/asm/kvm.h' differs from latest version at 'arch/arm64/include/uapi/asm/kvm.h': 190> void __user *addr;
Warning: Kernel ABI header at 'tools/arch/arm64/include/uapi/asm/kvm.h' differs from latest version at 'arch/arm64/include/uapi/asm/kvm.h': 191> __u64 flags;
Warning: Kernel ABI header at 'tools/arch/arm64/include/uapi/asm/kvm.h' differs from latest version at 'arch/arm64/include/uapi/asm/kvm.h': 192> __u64 reserved[2];
Warning: Kernel ABI header at 'tools/arch/arm64/include/uapi/asm/kvm.h' differs from latest version at 'arch/arm64/include/uapi/asm/kvm.h': 193> };
Warning: Kernel ABI header at 'tools/arch/arm64/include/uapi/asm/kvm.h' differs from latest version at 'arch/arm64/include/uapi/asm/kvm.h': 194>
Warning: Kernel ABI header at 'tools/arch/arm64/include/uapi/asm/kvm.h' differs from latest version at 'arch/arm64/include/uapi/asm/kvm.h': 195> #define KVM_ARM_TAGS_TO_GUEST 0
Warning: Kernel ABI header at 'tools/arch/arm64/include/uapi/asm/kvm.h' differs from latest version at 'arch/arm64/include/uapi/asm/kvm.h': 196> #define KVM_ARM_TAGS_FROM_GUEST 1
Warning: Kernel ABI header at 'tools/arch/arm64/include/uapi/asm/kvm.h' differs from latest version at 'arch/arm64/include/uapi/asm/kvm.h': 197>
>> Warning: Kernel ABI header at 'tools/arch/arm64/include/uapi/asm/kvm.h' differs from latest version at 'arch/arm64/include/uapi/asm/kvm.h': 368> #define KVM_ARM_VCPU_TIMER_OFFSET_VTIMER 2
---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all(a)lists.01.org
^ permalink raw reply [flat|nested] 4+ messages in thread* [PATCH v2 00/12] KVM: Add idempotent controls for migrating system counter state
@ 2021-07-16 21:26 Oliver Upton
2021-07-16 21:26 ` Oliver Upton
0 siblings, 1 reply; 4+ messages in thread
From: Oliver Upton @ 2021-07-16 21:26 UTC (permalink / raw)
To: kvm, kvmarm
Cc: Marc Zyngier, Raghavendra Rao Anata, Peter Shier,
Sean Christopherson, David Matlack, Paolo Bonzini,
linux-arm-kernel, Jim Mattson
KVM's current means of saving/restoring system counters is plagued with
temporal issues. At least on ARM64 and x86, we migrate the guest's
system counter by-value through the respective guest system register
values (cntvct_el0, ia32_tsc). Restoring system counters by-value is
brittle as the state is not idempotent: the host system counter is still
oscillating between the attempted save and restore. Furthermore, VMMs
may wish to transparently live migrate guest VMs, meaning that they
include the elapsed time due to live migration blackout in the guest
system counter view. The VMM thread could be preempted for any number of
reasons (scheduler, L0 hypervisor under nested) between the time that
it calculates the desired guest counter value and when KVM actually sets
this counter state.
Despite the value-based interface that we present to userspace, KVM
actually has idempotent guest controls by way of system counter offsets.
We can avoid all of the issues associated with a value-based interface
by abstracting these offset controls in new ioctls. This series
introduces new vCPU device attributes to provide userspace access to the
vCPU's system counter offset.
Patch 1 adopts Paolo's suggestion, augmenting the KVM_{GET,SET}_CLOCK
ioctls to provide userspace with a (host_tsc, realtime) instant. This is
essential for a VMM to perform precise migration of the guest's system
counters.
Patches 2-3 add support for x86 by shoehorning the new controls into the
pre-existing synchronization heuristics.
Patches 4-5 implement a test for the new additions to
KVM_{GET,SET}_CLOCK.
Patches 6-7 implement at test for the tsc offset attribute introduced in
patch 3.
Patch 8 adds a device attribute for the arm64 virtual counter-timer
offset.
Patch 9 extends the test from patch 7 to cover the arm64 virtual
counter-timer offset.
Patch 10 adds a device attribute for the arm64 physical counter-timer
offset. Currently, this is implemented as a synthetic register, forcing
the guest to trap to the host and emulating the offset in the fast exit
path. Later down the line we will have hardware with FEAT_ECV, which
allows the hypervisor to perform physical counter-timer offsetting in
hardware (CNTPOFF_EL2).
Patch 11 extends the test from patch 7 to cover the arm64 physical
counter-timer offset.
Patch 12 introduces a benchmark to measure the overhead of emulation in
patch 10.
Physical counter benchmark
--------------------------
The following data was collected by running 10000 iterations of the
benchmark test from Patch 6 on an Ampere Mt. Jade reference server, A 2S
machine with 2 80-core Ampere Altra SoCs. Measurements were collected
for both VHE and nVHE operation using the `kvm-arm.mode=` command-line
parameter.
nVHE
----
+--------------------+--------+---------+
| Metric | Native | Trapped |
+--------------------+--------+---------+
| Average | 54ns | 148ns |
| Standard Deviation | 124ns | 122ns |
| 95th Percentile | 258ns | 348ns |
+--------------------+--------+---------+
VHE
---
+--------------------+--------+---------+
| Metric | Native | Trapped |
+--------------------+--------+---------+
| Average | 53ns | 152ns |
| Standard Deviation | 92ns | 94ns |
| 95th Percentile | 204ns | 307ns |
+--------------------+--------+---------+
This series applies cleanly to the following commit:
1889228d80fe ("KVM: selftests: smm_test: Test SMM enter from L2")
v1 -> v2:
- Reimplemented as vCPU device attributes instead of a distinct ioctl.
- Added the (realtime, host_tsc) instant support to
KVM_{GET,SET}_CLOCK
- Changed the arm64 implementation to broadcast counter offset values
to all vCPUs in a guest. This upholds the architectural expectations
of a consistent counter-timer across CPUs.
- Fixed a bug with traps in VHE mode. We now configure traps on every
transition into a guest to handle differing VMs (trapped, emulated).
Oliver Upton (12):
KVM: x86: Report host tsc and realtime values in KVM_GET_CLOCK
KVM: x86: Refactor tsc synchronization code
KVM: x86: Expose TSC offset controls to userspace
tools: arch: x86: pull in pvclock headers
selftests: KVM: Add test for KVM_{GET,SET}_CLOCK
selftests: KVM: Add helpers for vCPU device attributes
selftests: KVM: Introduce system counter offset test
KVM: arm64: Allow userspace to configure a vCPU's virtual offset
selftests: KVM: Add support for aarch64 to system_counter_offset_test
KVM: arm64: Provide userspace access to the physical counter offset
selftests: KVM: Test physical counter offsetting
selftests: KVM: Add counter emulation benchmark
Documentation/virt/kvm/api.rst | 42 +-
Documentation/virt/kvm/locking.rst | 11 +
arch/arm64/include/asm/kvm_host.h | 1 +
arch/arm64/include/asm/kvm_hyp.h | 2 -
arch/arm64/include/asm/sysreg.h | 1 +
arch/arm64/include/uapi/asm/kvm.h | 2 +
arch/arm64/kvm/arch_timer.c | 118 ++++-
arch/arm64/kvm/arm.c | 4 +-
arch/arm64/kvm/hyp/include/hyp/switch.h | 23 +
arch/arm64/kvm/hyp/include/hyp/timer-sr.h | 26 ++
arch/arm64/kvm/hyp/nvhe/switch.c | 2 -
arch/arm64/kvm/hyp/nvhe/timer-sr.c | 21 +-
arch/arm64/kvm/hyp/vhe/timer-sr.c | 27 ++
arch/x86/include/asm/kvm_host.h | 4 +
arch/x86/include/uapi/asm/kvm.h | 4 +
arch/x86/kvm/x86.c | 421 ++++++++++++++----
include/kvm/arm_arch_timer.h | 2 -
include/uapi/linux/kvm.h | 7 +-
tools/arch/x86/include/asm/pvclock-abi.h | 48 ++
tools/arch/x86/include/asm/pvclock.h | 103 +++++
tools/testing/selftests/kvm/.gitignore | 3 +
tools/testing/selftests/kvm/Makefile | 4 +
.../kvm/aarch64/counter_emulation_benchmark.c | 215 +++++++++
.../selftests/kvm/include/aarch64/processor.h | 24 +
.../testing/selftests/kvm/include/kvm_util.h | 11 +
tools/testing/selftests/kvm/lib/kvm_util.c | 38 ++
.../kvm/system_counter_offset_test.c | 206 +++++++++
.../selftests/kvm/x86_64/kvm_clock_test.c | 210 +++++++++
28 files changed, 1447 insertions(+), 133 deletions(-)
create mode 100644 arch/arm64/kvm/hyp/include/hyp/timer-sr.h
create mode 100644 tools/arch/x86/include/asm/pvclock-abi.h
create mode 100644 tools/arch/x86/include/asm/pvclock.h
create mode 100644 tools/testing/selftests/kvm/aarch64/counter_emulation_benchmark.c
create mode 100644 tools/testing/selftests/kvm/system_counter_offset_test.c
create mode 100644 tools/testing/selftests/kvm/x86_64/kvm_clock_test.c
--
2.32.0.402.g57bb445576-goog
_______________________________________________
kvmarm mailing list
kvmarm@lists.cs.columbia.edu
https://lists.cs.columbia.edu/mailman/listinfo/kvmarm
^ permalink raw reply [flat|nested] 4+ messages in thread* [PATCH v2 08/12] KVM: arm64: Allow userspace to configure a vCPU's virtual offset
2021-07-16 21:26 [PATCH v2 00/12] KVM: Add idempotent controls for migrating system counter state Oliver Upton
2021-07-16 21:26 ` Oliver Upton
@ 2021-07-16 21:26 ` Oliver Upton
0 siblings, 0 replies; 4+ messages in thread
From: Oliver Upton @ 2021-07-16 21:26 UTC (permalink / raw)
To: kvm, kvmarm
Cc: Marc Zyngier, Raghavendra Rao Anata, Peter Shier,
Sean Christopherson, David Matlack, Paolo Bonzini,
linux-arm-kernel, Jim Mattson
Add a new vCPU attribute that allows userspace to directly manipulate
the virtual counter-timer offset. Exposing such an interface allows for
the precise migration of guest virtual counter-timers, as it is an
indepotent interface.
Uphold the existing behavior of writes to CNTVOFF_EL2 for this new
interface, wherein a write to a single vCPU is broadcasted to all vCPUs
within a VM.
Signed-off-by: Oliver Upton <oupton@google.com>
---
arch/arm64/include/uapi/asm/kvm.h | 1 +
arch/arm64/kvm/arch_timer.c | 68 ++++++++++++++++++++++++++++++-
2 files changed, 67 insertions(+), 2 deletions(-)
diff --git a/arch/arm64/include/uapi/asm/kvm.h b/arch/arm64/include/uapi/asm/kvm.h
index b3edde68bc3e..008d0518d2b1 100644
--- a/arch/arm64/include/uapi/asm/kvm.h
+++ b/arch/arm64/include/uapi/asm/kvm.h
@@ -365,6 +365,7 @@ struct kvm_arm_copy_mte_tags {
#define KVM_ARM_VCPU_TIMER_CTRL 1
#define KVM_ARM_VCPU_TIMER_IRQ_VTIMER 0
#define KVM_ARM_VCPU_TIMER_IRQ_PTIMER 1
+#define KVM_ARM_VCPU_TIMER_OFFSET_VTIMER 2
#define KVM_ARM_VCPU_PVTIME_CTRL 2
#define KVM_ARM_VCPU_PVTIME_IPA 0
diff --git a/arch/arm64/kvm/arch_timer.c b/arch/arm64/kvm/arch_timer.c
index 3df67c127489..d2b1b13af658 100644
--- a/arch/arm64/kvm/arch_timer.c
+++ b/arch/arm64/kvm/arch_timer.c
@@ -1305,7 +1305,7 @@ static void set_timer_irqs(struct kvm *kvm, int vtimer_irq, int ptimer_irq)
}
}
-int kvm_arm_timer_set_attr(struct kvm_vcpu *vcpu, struct kvm_device_attr *attr)
+int kvm_arm_timer_set_attr_irq(struct kvm_vcpu *vcpu, struct kvm_device_attr *attr)
{
int __user *uaddr = (int __user *)(long)attr->addr;
struct arch_timer_context *vtimer = vcpu_vtimer(vcpu);
@@ -1338,7 +1338,39 @@ int kvm_arm_timer_set_attr(struct kvm_vcpu *vcpu, struct kvm_device_attr *attr)
return 0;
}
-int kvm_arm_timer_get_attr(struct kvm_vcpu *vcpu, struct kvm_device_attr *attr)
+int kvm_arm_timer_set_attr_offset(struct kvm_vcpu *vcpu, struct kvm_device_attr *attr)
+{
+ u64 __user *uaddr = (u64 __user *)(long)attr->addr;
+ u64 offset;
+
+ if (get_user(offset, uaddr))
+ return -EFAULT;
+
+ switch (attr->attr) {
+ case KVM_ARM_VCPU_TIMER_OFFSET_VTIMER:
+ update_vtimer_cntvoff(vcpu, offset);
+ break;
+ default:
+ return -ENXIO;
+ }
+
+ return 0;
+}
+
+int kvm_arm_timer_set_attr(struct kvm_vcpu *vcpu, struct kvm_device_attr *attr)
+{
+ switch (attr->attr) {
+ case KVM_ARM_VCPU_TIMER_IRQ_VTIMER:
+ case KVM_ARM_VCPU_TIMER_IRQ_PTIMER:
+ return kvm_arm_timer_set_attr_irq(vcpu, attr);
+ case KVM_ARM_VCPU_TIMER_OFFSET_VTIMER:
+ return kvm_arm_timer_set_attr_offset(vcpu, attr);
+ }
+
+ return -ENXIO;
+}
+
+int kvm_arm_timer_get_attr_irq(struct kvm_vcpu *vcpu, struct kvm_device_attr *attr)
{
int __user *uaddr = (int __user *)(long)attr->addr;
struct arch_timer_context *timer;
@@ -1359,11 +1391,43 @@ int kvm_arm_timer_get_attr(struct kvm_vcpu *vcpu, struct kvm_device_attr *attr)
return put_user(irq, uaddr);
}
+int kvm_arm_timer_get_attr_offset(struct kvm_vcpu *vcpu, struct kvm_device_attr *attr)
+{
+ u64 __user *uaddr = (u64 __user *)(long)attr->addr;
+ struct arch_timer_context *timer;
+ u64 offset;
+
+ switch (attr->attr) {
+ case KVM_ARM_VCPU_TIMER_OFFSET_VTIMER:
+ timer = vcpu_vtimer(vcpu);
+ break;
+ default:
+ return -ENXIO;
+ }
+
+ offset = timer_get_offset(timer);
+ return put_user(offset, uaddr);
+}
+
+int kvm_arm_timer_get_attr(struct kvm_vcpu *vcpu, struct kvm_device_attr *attr)
+{
+ switch (attr->attr) {
+ case KVM_ARM_VCPU_TIMER_IRQ_VTIMER:
+ case KVM_ARM_VCPU_TIMER_IRQ_PTIMER:
+ return kvm_arm_timer_get_attr_irq(vcpu, attr);
+ case KVM_ARM_VCPU_TIMER_OFFSET_VTIMER:
+ return kvm_arm_timer_get_attr_offset(vcpu, attr);
+ }
+
+ return -ENXIO;
+}
+
int kvm_arm_timer_has_attr(struct kvm_vcpu *vcpu, struct kvm_device_attr *attr)
{
switch (attr->attr) {
case KVM_ARM_VCPU_TIMER_IRQ_VTIMER:
case KVM_ARM_VCPU_TIMER_IRQ_PTIMER:
+ case KVM_ARM_VCPU_TIMER_OFFSET_VTIMER:
return 0;
}
--
2.32.0.402.g57bb445576-goog
_______________________________________________
kvmarm mailing list
kvmarm@lists.cs.columbia.edu
https://lists.cs.columbia.edu/mailman/listinfo/kvmarm
^ permalink raw reply related [flat|nested] 4+ messages in thread* [PATCH v2 08/12] KVM: arm64: Allow userspace to configure a vCPU's virtual offset
@ 2021-07-16 21:26 ` Oliver Upton
0 siblings, 0 replies; 4+ messages in thread
From: Oliver Upton @ 2021-07-16 21:26 UTC (permalink / raw)
To: kvm, kvmarm
Cc: Paolo Bonzini, Sean Christopherson, Marc Zyngier, Peter Shier,
Jim Mattson, David Matlack, Ricardo Koller, Jing Zhang,
Raghavendra Rao Anata, James Morse, Alexandru Elisei,
Suzuki K Poulose, linux-arm-kernel, Oliver Upton
Add a new vCPU attribute that allows userspace to directly manipulate
the virtual counter-timer offset. Exposing such an interface allows for
the precise migration of guest virtual counter-timers, as it is an
indepotent interface.
Uphold the existing behavior of writes to CNTVOFF_EL2 for this new
interface, wherein a write to a single vCPU is broadcasted to all vCPUs
within a VM.
Signed-off-by: Oliver Upton <oupton@google.com>
---
arch/arm64/include/uapi/asm/kvm.h | 1 +
arch/arm64/kvm/arch_timer.c | 68 ++++++++++++++++++++++++++++++-
2 files changed, 67 insertions(+), 2 deletions(-)
diff --git a/arch/arm64/include/uapi/asm/kvm.h b/arch/arm64/include/uapi/asm/kvm.h
index b3edde68bc3e..008d0518d2b1 100644
--- a/arch/arm64/include/uapi/asm/kvm.h
+++ b/arch/arm64/include/uapi/asm/kvm.h
@@ -365,6 +365,7 @@ struct kvm_arm_copy_mte_tags {
#define KVM_ARM_VCPU_TIMER_CTRL 1
#define KVM_ARM_VCPU_TIMER_IRQ_VTIMER 0
#define KVM_ARM_VCPU_TIMER_IRQ_PTIMER 1
+#define KVM_ARM_VCPU_TIMER_OFFSET_VTIMER 2
#define KVM_ARM_VCPU_PVTIME_CTRL 2
#define KVM_ARM_VCPU_PVTIME_IPA 0
diff --git a/arch/arm64/kvm/arch_timer.c b/arch/arm64/kvm/arch_timer.c
index 3df67c127489..d2b1b13af658 100644
--- a/arch/arm64/kvm/arch_timer.c
+++ b/arch/arm64/kvm/arch_timer.c
@@ -1305,7 +1305,7 @@ static void set_timer_irqs(struct kvm *kvm, int vtimer_irq, int ptimer_irq)
}
}
-int kvm_arm_timer_set_attr(struct kvm_vcpu *vcpu, struct kvm_device_attr *attr)
+int kvm_arm_timer_set_attr_irq(struct kvm_vcpu *vcpu, struct kvm_device_attr *attr)
{
int __user *uaddr = (int __user *)(long)attr->addr;
struct arch_timer_context *vtimer = vcpu_vtimer(vcpu);
@@ -1338,7 +1338,39 @@ int kvm_arm_timer_set_attr(struct kvm_vcpu *vcpu, struct kvm_device_attr *attr)
return 0;
}
-int kvm_arm_timer_get_attr(struct kvm_vcpu *vcpu, struct kvm_device_attr *attr)
+int kvm_arm_timer_set_attr_offset(struct kvm_vcpu *vcpu, struct kvm_device_attr *attr)
+{
+ u64 __user *uaddr = (u64 __user *)(long)attr->addr;
+ u64 offset;
+
+ if (get_user(offset, uaddr))
+ return -EFAULT;
+
+ switch (attr->attr) {
+ case KVM_ARM_VCPU_TIMER_OFFSET_VTIMER:
+ update_vtimer_cntvoff(vcpu, offset);
+ break;
+ default:
+ return -ENXIO;
+ }
+
+ return 0;
+}
+
+int kvm_arm_timer_set_attr(struct kvm_vcpu *vcpu, struct kvm_device_attr *attr)
+{
+ switch (attr->attr) {
+ case KVM_ARM_VCPU_TIMER_IRQ_VTIMER:
+ case KVM_ARM_VCPU_TIMER_IRQ_PTIMER:
+ return kvm_arm_timer_set_attr_irq(vcpu, attr);
+ case KVM_ARM_VCPU_TIMER_OFFSET_VTIMER:
+ return kvm_arm_timer_set_attr_offset(vcpu, attr);
+ }
+
+ return -ENXIO;
+}
+
+int kvm_arm_timer_get_attr_irq(struct kvm_vcpu *vcpu, struct kvm_device_attr *attr)
{
int __user *uaddr = (int __user *)(long)attr->addr;
struct arch_timer_context *timer;
@@ -1359,11 +1391,43 @@ int kvm_arm_timer_get_attr(struct kvm_vcpu *vcpu, struct kvm_device_attr *attr)
return put_user(irq, uaddr);
}
+int kvm_arm_timer_get_attr_offset(struct kvm_vcpu *vcpu, struct kvm_device_attr *attr)
+{
+ u64 __user *uaddr = (u64 __user *)(long)attr->addr;
+ struct arch_timer_context *timer;
+ u64 offset;
+
+ switch (attr->attr) {
+ case KVM_ARM_VCPU_TIMER_OFFSET_VTIMER:
+ timer = vcpu_vtimer(vcpu);
+ break;
+ default:
+ return -ENXIO;
+ }
+
+ offset = timer_get_offset(timer);
+ return put_user(offset, uaddr);
+}
+
+int kvm_arm_timer_get_attr(struct kvm_vcpu *vcpu, struct kvm_device_attr *attr)
+{
+ switch (attr->attr) {
+ case KVM_ARM_VCPU_TIMER_IRQ_VTIMER:
+ case KVM_ARM_VCPU_TIMER_IRQ_PTIMER:
+ return kvm_arm_timer_get_attr_irq(vcpu, attr);
+ case KVM_ARM_VCPU_TIMER_OFFSET_VTIMER:
+ return kvm_arm_timer_get_attr_offset(vcpu, attr);
+ }
+
+ return -ENXIO;
+}
+
int kvm_arm_timer_has_attr(struct kvm_vcpu *vcpu, struct kvm_device_attr *attr)
{
switch (attr->attr) {
case KVM_ARM_VCPU_TIMER_IRQ_VTIMER:
case KVM_ARM_VCPU_TIMER_IRQ_PTIMER:
+ case KVM_ARM_VCPU_TIMER_OFFSET_VTIMER:
return 0;
}
--
2.32.0.402.g57bb445576-goog
^ permalink raw reply related [flat|nested] 4+ messages in thread* [PATCH v2 08/12] KVM: arm64: Allow userspace to configure a vCPU's virtual offset
@ 2021-07-16 21:26 ` Oliver Upton
0 siblings, 0 replies; 4+ messages in thread
From: Oliver Upton @ 2021-07-16 21:26 UTC (permalink / raw)
To: kvm, kvmarm
Cc: Paolo Bonzini, Sean Christopherson, Marc Zyngier, Peter Shier,
Jim Mattson, David Matlack, Ricardo Koller, Jing Zhang,
Raghavendra Rao Anata, James Morse, Alexandru Elisei,
Suzuki K Poulose, linux-arm-kernel, Oliver Upton
Add a new vCPU attribute that allows userspace to directly manipulate
the virtual counter-timer offset. Exposing such an interface allows for
the precise migration of guest virtual counter-timers, as it is an
indepotent interface.
Uphold the existing behavior of writes to CNTVOFF_EL2 for this new
interface, wherein a write to a single vCPU is broadcasted to all vCPUs
within a VM.
Signed-off-by: Oliver Upton <oupton@google.com>
---
arch/arm64/include/uapi/asm/kvm.h | 1 +
arch/arm64/kvm/arch_timer.c | 68 ++++++++++++++++++++++++++++++-
2 files changed, 67 insertions(+), 2 deletions(-)
diff --git a/arch/arm64/include/uapi/asm/kvm.h b/arch/arm64/include/uapi/asm/kvm.h
index b3edde68bc3e..008d0518d2b1 100644
--- a/arch/arm64/include/uapi/asm/kvm.h
+++ b/arch/arm64/include/uapi/asm/kvm.h
@@ -365,6 +365,7 @@ struct kvm_arm_copy_mte_tags {
#define KVM_ARM_VCPU_TIMER_CTRL 1
#define KVM_ARM_VCPU_TIMER_IRQ_VTIMER 0
#define KVM_ARM_VCPU_TIMER_IRQ_PTIMER 1
+#define KVM_ARM_VCPU_TIMER_OFFSET_VTIMER 2
#define KVM_ARM_VCPU_PVTIME_CTRL 2
#define KVM_ARM_VCPU_PVTIME_IPA 0
diff --git a/arch/arm64/kvm/arch_timer.c b/arch/arm64/kvm/arch_timer.c
index 3df67c127489..d2b1b13af658 100644
--- a/arch/arm64/kvm/arch_timer.c
+++ b/arch/arm64/kvm/arch_timer.c
@@ -1305,7 +1305,7 @@ static void set_timer_irqs(struct kvm *kvm, int vtimer_irq, int ptimer_irq)
}
}
-int kvm_arm_timer_set_attr(struct kvm_vcpu *vcpu, struct kvm_device_attr *attr)
+int kvm_arm_timer_set_attr_irq(struct kvm_vcpu *vcpu, struct kvm_device_attr *attr)
{
int __user *uaddr = (int __user *)(long)attr->addr;
struct arch_timer_context *vtimer = vcpu_vtimer(vcpu);
@@ -1338,7 +1338,39 @@ int kvm_arm_timer_set_attr(struct kvm_vcpu *vcpu, struct kvm_device_attr *attr)
return 0;
}
-int kvm_arm_timer_get_attr(struct kvm_vcpu *vcpu, struct kvm_device_attr *attr)
+int kvm_arm_timer_set_attr_offset(struct kvm_vcpu *vcpu, struct kvm_device_attr *attr)
+{
+ u64 __user *uaddr = (u64 __user *)(long)attr->addr;
+ u64 offset;
+
+ if (get_user(offset, uaddr))
+ return -EFAULT;
+
+ switch (attr->attr) {
+ case KVM_ARM_VCPU_TIMER_OFFSET_VTIMER:
+ update_vtimer_cntvoff(vcpu, offset);
+ break;
+ default:
+ return -ENXIO;
+ }
+
+ return 0;
+}
+
+int kvm_arm_timer_set_attr(struct kvm_vcpu *vcpu, struct kvm_device_attr *attr)
+{
+ switch (attr->attr) {
+ case KVM_ARM_VCPU_TIMER_IRQ_VTIMER:
+ case KVM_ARM_VCPU_TIMER_IRQ_PTIMER:
+ return kvm_arm_timer_set_attr_irq(vcpu, attr);
+ case KVM_ARM_VCPU_TIMER_OFFSET_VTIMER:
+ return kvm_arm_timer_set_attr_offset(vcpu, attr);
+ }
+
+ return -ENXIO;
+}
+
+int kvm_arm_timer_get_attr_irq(struct kvm_vcpu *vcpu, struct kvm_device_attr *attr)
{
int __user *uaddr = (int __user *)(long)attr->addr;
struct arch_timer_context *timer;
@@ -1359,11 +1391,43 @@ int kvm_arm_timer_get_attr(struct kvm_vcpu *vcpu, struct kvm_device_attr *attr)
return put_user(irq, uaddr);
}
+int kvm_arm_timer_get_attr_offset(struct kvm_vcpu *vcpu, struct kvm_device_attr *attr)
+{
+ u64 __user *uaddr = (u64 __user *)(long)attr->addr;
+ struct arch_timer_context *timer;
+ u64 offset;
+
+ switch (attr->attr) {
+ case KVM_ARM_VCPU_TIMER_OFFSET_VTIMER:
+ timer = vcpu_vtimer(vcpu);
+ break;
+ default:
+ return -ENXIO;
+ }
+
+ offset = timer_get_offset(timer);
+ return put_user(offset, uaddr);
+}
+
+int kvm_arm_timer_get_attr(struct kvm_vcpu *vcpu, struct kvm_device_attr *attr)
+{
+ switch (attr->attr) {
+ case KVM_ARM_VCPU_TIMER_IRQ_VTIMER:
+ case KVM_ARM_VCPU_TIMER_IRQ_PTIMER:
+ return kvm_arm_timer_get_attr_irq(vcpu, attr);
+ case KVM_ARM_VCPU_TIMER_OFFSET_VTIMER:
+ return kvm_arm_timer_get_attr_offset(vcpu, attr);
+ }
+
+ return -ENXIO;
+}
+
int kvm_arm_timer_has_attr(struct kvm_vcpu *vcpu, struct kvm_device_attr *attr)
{
switch (attr->attr) {
case KVM_ARM_VCPU_TIMER_IRQ_VTIMER:
case KVM_ARM_VCPU_TIMER_IRQ_PTIMER:
+ case KVM_ARM_VCPU_TIMER_OFFSET_VTIMER:
return 0;
}
--
2.32.0.402.g57bb445576-goog
_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
^ permalink raw reply related [flat|nested] 4+ messages in thread
end of thread, other threads:[~2021-07-18 20:23 UTC | newest]
Thread overview: 4+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2021-07-18 20:23 [PATCH v2 08/12] KVM: arm64: Allow userspace to configure a vCPU's virtual offset kernel test robot
-- strict thread matches above, loose matches on Subject: below --
2021-07-16 21:26 [PATCH v2 00/12] KVM: Add idempotent controls for migrating system counter state Oliver Upton
2021-07-16 21:26 ` [PATCH v2 08/12] KVM: arm64: Allow userspace to configure a vCPU's virtual offset Oliver Upton
2021-07-16 21:26 ` Oliver Upton
2021-07-16 21:26 ` Oliver Upton
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.