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,
Andrew Jones <drjones@redhat.com>, Will Deacon <will@kernel.org>,
Catalin Marinas <catalin.marinas@arm.com>,
Oliver Upton <oupton@google.com>
Subject: [PATCH v6 03/21] KVM: x86: Take the pvclock sync lock behind the tsc_write_lock
Date: Wed, 4 Aug 2021 08:58:01 +0000 [thread overview]
Message-ID: <20210804085819.846610-4-oupton@google.com> (raw)
In-Reply-To: <20210804085819.846610-1-oupton@google.com>
A later change requires that the pvclock sync lock be taken while
holding the tsc_write_lock. Change the locking in kvm_synchronize_tsc()
to align with the requirement to isolate the locking change to its own
commit.
Cc: Sean Christopherson <seanjc@google.com>
Signed-off-by: Oliver Upton <oupton@google.com>
---
Documentation/virt/kvm/locking.rst | 11 +++++++++++
arch/x86/kvm/x86.c | 2 +-
2 files changed, 12 insertions(+), 1 deletion(-)
diff --git a/Documentation/virt/kvm/locking.rst b/Documentation/virt/kvm/locking.rst
index 8138201efb09..0bf346adac2a 100644
--- a/Documentation/virt/kvm/locking.rst
+++ b/Documentation/virt/kvm/locking.rst
@@ -36,6 +36,9 @@ On x86:
holding kvm->arch.mmu_lock (typically with ``read_lock``, otherwise
there's no need to take kvm->arch.tdp_mmu_pages_lock at all).
+- kvm->arch.tsc_write_lock is taken outside
+ kvm->arch.pvclock_gtod_sync_lock
+
Everything else is a leaf: no other lock is taken inside the critical
sections.
@@ -222,6 +225,14 @@ time it will be set using the Dirty tracking mechanism described above.
:Comment: 'raw' because hardware enabling/disabling must be atomic /wrt
migration.
+:Name: kvm_arch::pvclock_gtod_sync_lock
+:Type: raw_spinlock_t
+:Arch: x86
+:Protects: kvm_arch::{cur_tsc_generation,cur_tsc_nsec,cur_tsc_write,
+ cur_tsc_offset,nr_vcpus_matched_tsc}
+:Comment: 'raw' because updating the kvm master clock must not be
+ preempted.
+
:Name: kvm_arch::tsc_write_lock
:Type: raw_spinlock
:Arch: x86
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 26f1fa263192..93b449761fbe 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -2529,7 +2529,6 @@ static void kvm_synchronize_tsc(struct kvm_vcpu *vcpu, u64 data)
vcpu->arch.this_tsc_write = kvm->arch.cur_tsc_write;
kvm_vcpu_write_tsc_offset(vcpu, offset);
- raw_spin_unlock_irqrestore(&kvm->arch.tsc_write_lock, flags);
spin_lock_irqsave(&kvm->arch.pvclock_gtod_sync_lock, flags);
if (!matched) {
@@ -2540,6 +2539,7 @@ static void kvm_synchronize_tsc(struct kvm_vcpu *vcpu, u64 data)
kvm_track_tsc_matching(vcpu);
spin_unlock_irqrestore(&kvm->arch.pvclock_gtod_sync_lock, flags);
+ raw_spin_unlock_irqrestore(&kvm->arch.tsc_write_lock, flags);
}
static inline void adjust_tsc_offset_guest(struct kvm_vcpu *vcpu,
--
2.32.0.605.g8dce9f2422-goog
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next prev parent reply other threads:[~2021-08-04 9:01 UTC|newest]
Thread overview: 51+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-08-04 8:57 [PATCH v6 00/21] KVM: Add idempotent controls for migrating system counter state Oliver Upton
2021-08-04 8:57 ` [PATCH v6 01/21] KVM: x86: Fix potential race in KVM_GET_CLOCK Oliver Upton
2021-08-11 12:23 ` Paolo Bonzini
2021-08-13 10:39 ` Oliver Upton
2021-08-13 10:44 ` Paolo Bonzini
2021-08-13 17:46 ` Oliver Upton
2021-08-04 8:58 ` [PATCH v6 02/21] KVM: x86: Report host tsc and realtime values " Oliver Upton
2021-08-04 8:58 ` Oliver Upton [this message]
2021-08-04 8:58 ` [PATCH v6 04/21] KVM: x86: Refactor tsc synchronization code Oliver Upton
2021-08-04 8:58 ` [PATCH v6 05/21] KVM: x86: Expose TSC offset controls to userspace Oliver Upton
2021-08-04 8:58 ` [PATCH v6 06/21] tools: arch: x86: pull in pvclock headers Oliver Upton
2021-08-04 8:58 ` [PATCH v6 07/21] selftests: KVM: Add test for KVM_{GET,SET}_CLOCK Oliver Upton
2021-08-04 8:58 ` [PATCH v6 08/21] selftests: KVM: Fix kvm device helper ioctl assertions Oliver Upton
2021-08-04 8:58 ` [PATCH v6 09/21] selftests: KVM: Add helpers for vCPU device attributes Oliver Upton
2021-08-04 8:58 ` [PATCH v6 10/21] selftests: KVM: Introduce system counter offset test Oliver Upton
2021-08-04 8:58 ` [PATCH v6 11/21] KVM: arm64: Refactor update_vtimer_cntvoff() Oliver Upton
2021-08-04 9:23 ` Andrew Jones
2021-08-04 8:58 ` [PATCH v6 12/21] KVM: arm64: Separate guest/host counter offset values Oliver Upton
2021-08-04 10:19 ` Andrew Jones
2021-08-04 8:58 ` [PATCH v6 13/21] KVM: arm64: Allow userspace to configure a vCPU's virtual offset Oliver Upton
2021-08-04 10:20 ` Andrew Jones
2021-08-10 9:35 ` Marc Zyngier
2021-08-10 9:44 ` Oliver Upton
2021-08-11 15:22 ` Marc Zyngier
2021-08-04 8:58 ` [PATCH v6 14/21] selftests: KVM: Add helper to check for register presence Oliver Upton
2021-08-04 9:14 ` Andrew Jones
2021-08-04 8:58 ` [PATCH v6 15/21] selftests: KVM: Add support for aarch64 to system_counter_offset_test Oliver Upton
2021-08-04 8:58 ` [PATCH v6 16/21] arm64: cpufeature: Enumerate support for Enhanced Counter Virtualization Oliver Upton
2021-08-10 9:38 ` Marc Zyngier
2021-08-04 8:58 ` [PATCH v6 17/21] KVM: arm64: Allow userspace to configure a guest's counter-timer offset Oliver Upton
2021-08-04 10:17 ` Andrew Jones
2021-08-04 10:22 ` Oliver Upton
2021-08-10 10:56 ` Marc Zyngier
2021-08-10 17:55 ` Oliver Upton
2021-08-11 9:01 ` Marc Zyngier
2021-08-04 8:58 ` [PATCH v6 18/21] KVM: arm64: Configure timer traps in vcpu_load() for VHE Oliver Upton
2021-08-04 10:25 ` Andrew Jones
2021-08-04 8:58 ` [PATCH v6 19/21] KVM: arm64: Emulate physical counter offsetting on non-ECV systems Oliver Upton
2021-08-04 11:05 ` Andrew Jones
2021-08-05 6:27 ` Oliver Upton
2021-08-10 11:27 ` Marc Zyngier
2021-08-04 8:58 ` [PATCH v6 20/21] selftests: KVM: Test physical counter offsetting Oliver Upton
2021-08-04 11:03 ` Andrew Jones
2021-08-04 8:58 ` [PATCH v6 21/21] selftests: KVM: Add counter emulation benchmark Oliver Upton
2021-08-04 11:05 ` [PATCH v6 00/21] KVM: Add idempotent controls for migrating system counter state Oliver Upton
2021-08-04 22:03 ` Oliver Upton
2021-08-10 0:04 ` Oliver Upton
2021-08-10 12:30 ` Marc Zyngier
2021-08-11 13:05 ` Paolo Bonzini
2021-08-11 18:56 ` Oliver Upton
2021-08-11 19:01 ` Marc Zyngier
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