From: Oliver Upton <oupton@google.com>
To: kvm@vger.kernel.org, kvmarm@lists.cs.columbia.edu
Cc: Paolo Bonzini <pbonzini@redhat.com>,
Sean Christopherson <seanjc@google.com>,
Marc Zyngier <maz@kernel.org>, Peter Shier <pshier@google.com>,
Jim Mattson <jmattson@google.com>,
David Matlack <dmatlack@google.com>,
Ricardo Koller <ricarkol@google.com>,
Jing Zhang <jingzhangos@google.com>,
Raghavendra Rao Anata <rananta@google.com>,
James Morse <james.morse@arm.com>,
Alexandru Elisei <alexandru.elisei@arm.com>,
Suzuki K Poulose <suzuki.poulose@arm.com>,
linux-arm-kernel@lists.infradead.org,
Oliver Upton <oupton@google.com>
Subject: [PATCH v3 08/12] KVM: arm64: Allow userspace to configure a vCPU's virtual offset
Date: Mon, 19 Jul 2021 18:49:45 +0000 [thread overview]
Message-ID: <20210719184949.1385910-9-oupton@google.com> (raw)
In-Reply-To: <20210719184949.1385910-1-oupton@google.com>
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>
---
Documentation/virt/kvm/devices/vcpu.rst | 22 ++++++++
arch/arm64/include/uapi/asm/kvm.h | 1 +
arch/arm64/kvm/arch_timer.c | 68 ++++++++++++++++++++++++-
3 files changed, 89 insertions(+), 2 deletions(-)
diff --git a/Documentation/virt/kvm/devices/vcpu.rst b/Documentation/virt/kvm/devices/vcpu.rst
index b46d5f742e69..7b57cba3416a 100644
--- a/Documentation/virt/kvm/devices/vcpu.rst
+++ b/Documentation/virt/kvm/devices/vcpu.rst
@@ -139,6 +139,28 @@ configured values on other VCPUs. Userspace should configure the interrupt
numbers on at least one VCPU after creating all VCPUs and before running any
VCPUs.
+2.2. ATTRIBUTE: KVM_ARM_VCPU_TIMER_OFFSET_VTIMER
+------------------------------------------------
+
+:Parameters: Pointer to a 64-bit unsigned counter-timer offset.
+
+Returns:
+
+ ======= ======================================
+ -EFAULT Error reading/writing the provided
+ parameter address
+ -ENXIO Attribute not supported
+ ======= ======================================
+
+Specifies the guest's virtual counter-timer offset from the host's
+virtual counter. The guest's virtual counter is then derived by
+the following equation:
+
+ guest_cntvct = host_cntvct - KVM_ARM_VCPU_TIMER_OFFSET_VTIMER
+
+KVM does not allow the use of varying offset values for different vCPUs;
+the last written offset value will be broadcasted to all vCPUs in a VM.
+
3. GROUP: KVM_ARM_VCPU_PVTIME_CTRL
==================================
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
next prev parent reply other threads:[~2021-07-19 21:20 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-07-19 18:49 [PATCH v3 00/12] KVM: Add idempotent controls for migrating system counter state Oliver Upton
2021-07-19 18:49 ` [PATCH v3 01/12] KVM: x86: Report host tsc and realtime values in KVM_GET_CLOCK Oliver Upton
2021-07-19 18:49 ` [PATCH v3 02/12] KVM: x86: Refactor tsc synchronization code Oliver Upton
2021-07-19 18:49 ` [PATCH v3 03/12] KVM: x86: Expose TSC offset controls to userspace Oliver Upton
2021-07-19 18:49 ` [PATCH v3 04/12] tools: arch: x86: pull in pvclock headers Oliver Upton
2021-07-19 18:49 ` [PATCH v3 05/12] selftests: KVM: Add test for KVM_{GET,SET}_CLOCK Oliver Upton
2021-07-19 18:49 ` [PATCH v3 06/12] selftests: KVM: Add helpers for vCPU device attributes Oliver Upton
2021-07-19 18:49 ` [PATCH v3 07/12] selftests: KVM: Introduce system counter offset test Oliver Upton
2021-07-19 18:49 ` Oliver Upton [this message]
2021-07-21 16:16 ` [PATCH v3 08/12] KVM: arm64: Allow userspace to configure a vCPU's virtual offset Andrew Jones
2021-07-19 18:49 ` [PATCH v3 09/12] selftests: KVM: Add support for aarch64 to system_counter_offset_test Oliver Upton
2021-07-21 16:26 ` Andrew Jones
2021-07-19 18:49 ` [PATCH v3 10/12] KVM: arm64: Provide userspace access to the physical counter offset Oliver Upton
2021-07-21 16:44 ` Andrew Jones
2021-07-19 18:49 ` [PATCH v3 11/12] selftests: KVM: Test physical counter offsetting Oliver Upton
2021-07-21 16:46 ` Andrew Jones
2021-07-19 18:49 ` [PATCH v3 12/12] selftests: KVM: Add counter emulation benchmark Oliver Upton
2021-07-21 18:59 ` Andrew Jones
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20210719184949.1385910-9-oupton@google.com \
--to=oupton@google.com \
--cc=alexandru.elisei@arm.com \
--cc=dmatlack@google.com \
--cc=james.morse@arm.com \
--cc=jingzhangos@google.com \
--cc=jmattson@google.com \
--cc=kvm@vger.kernel.org \
--cc=kvmarm@lists.cs.columbia.edu \
--cc=linux-arm-kernel@lists.infradead.org \
--cc=maz@kernel.org \
--cc=pbonzini@redhat.com \
--cc=pshier@google.com \
--cc=rananta@google.com \
--cc=ricarkol@google.com \
--cc=seanjc@google.com \
--cc=suzuki.poulose@arm.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).