From: Marc Zyngier <maz@kernel.org>
To: kvmarm@lists.linux.dev, kvm@vger.kernel.org,
linux-arm-kernel@lists.infradead.org
Cc: James Morse <james.morse@arm.com>,
Suzuki K Poulose <suzuki.poulose@arm.com>,
Oliver Upton <oliver.upton@linux.dev>,
Zenghui Yu <yuzenghui@huawei.com>,
Ricardo Koller <ricarkol@google.com>,
Simon Veith <sveith@amazon.de>,
Reiji Watanabe <reijiw@google.com>,
Colton Lewis <coltonlewis@google.com>,
Joey Gouly <joey.gouly@arm.com>,
dwmw2@infradead.org
Subject: [PATCH v2 02/19] KVM: arm64: timers: Use a per-vcpu, per-timer accumulator for fractional ns
Date: Mon, 13 Mar 2023 12:48:20 +0000 [thread overview]
Message-ID: <20230313124837.2264882-3-maz@kernel.org> (raw)
In-Reply-To: <20230313124837.2264882-1-maz@kernel.org>
Instead of accumulating the fractional ns value generated every time
we compute a ns delta in a global variable, use a per-vcpu, per-timer
variable. This keeps the fractional ns local to the timer instead of
contributing to any odd, unrelated timer.
Signed-off-by: Marc Zyngier <maz@kernel.org>
---
arch/arm64/kvm/arch_timer.c | 2 +-
include/kvm/arm_arch_timer.h | 1 +
2 files changed, 2 insertions(+), 1 deletion(-)
diff --git a/arch/arm64/kvm/arch_timer.c b/arch/arm64/kvm/arch_timer.c
index e1af4301b913..9515c645f03d 100644
--- a/arch/arm64/kvm/arch_timer.c
+++ b/arch/arm64/kvm/arch_timer.c
@@ -212,7 +212,7 @@ static u64 kvm_counter_compute_delta(struct arch_timer_context *timer_ctx,
ns = cyclecounter_cyc2ns(timecounter->cc,
val - now,
timecounter->mask,
- &timecounter->frac);
+ &timer_ctx->ns_frac);
return ns;
}
diff --git a/include/kvm/arm_arch_timer.h b/include/kvm/arm_arch_timer.h
index c52a6e6839da..70d47c4adc6a 100644
--- a/include/kvm/arm_arch_timer.h
+++ b/include/kvm/arm_arch_timer.h
@@ -44,6 +44,7 @@ struct arch_timer_context {
/* Emulated Timer (may be unused) */
struct hrtimer hrtimer;
+ u64 ns_frac;
/* Offset for this counter/timer */
struct arch_timer_offset offset;
--
2.34.1
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next prev parent reply other threads:[~2023-03-13 12:50 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-03-13 12:48 [PATCH v2 00/19] KVM: arm64: Rework timer offsetting for fun and profit Marc Zyngier
2023-03-13 12:48 ` [PATCH v2 01/19] KVM: arm64: timers: Convert per-vcpu virtual offset to a global value Marc Zyngier
2023-03-13 12:48 ` Marc Zyngier [this message]
2023-03-13 12:48 ` [PATCH v2 03/19] arm64: Add CNTPOFF_EL2 register definition Marc Zyngier
2023-03-13 12:48 ` [PATCH v2 04/19] arm64: Add HAS_ECV_CNTPOFF capability Marc Zyngier
2023-03-13 12:48 ` [PATCH v2 05/19] KVM: arm64: timers: Use CNTPOFF_EL2 to offset the physical timer Marc Zyngier
2023-03-13 12:48 ` [PATCH v2 06/19] KVM: arm64: timers: Allow physical offset without CNTPOFF_EL2 Marc Zyngier
2023-03-13 16:43 ` Marc Zyngier
2023-03-13 12:48 ` [PATCH v2 07/19] KVM: arm64: Expose {un,}lock_all_vcpus() to the reset of KVM Marc Zyngier
2023-03-13 12:48 ` [PATCH v2 08/19] KVM: arm64: timers: Allow userspace to set the global counter offset Marc Zyngier
2023-03-13 12:48 ` [PATCH v2 09/19] KVM: arm64: timers: Allow save/restoring of the physical timer Marc Zyngier
2023-03-13 12:48 ` [PATCH v2 10/19] KVM: arm64: timers: Rationalise per-vcpu timer init Marc Zyngier
2023-03-13 12:48 ` [PATCH v2 11/19] KVM: arm64: timers: Abstract per-timer IRQ access Marc Zyngier
2023-03-13 12:48 ` [PATCH v2 12/19] KVM: arm64: timers: Move the timer IRQs into arch_timer_vm_data Marc Zyngier
2023-03-13 12:48 ` [PATCH v2 13/19] KVM: arm64: Abstract the number of valid timers per vcpu Marc Zyngier
2023-03-13 12:48 ` [PATCH v2 14/19] KVM: arm64: Document KVM_ARM_SET_CNT_OFFSETS and co Marc Zyngier
2023-03-13 12:48 ` [PATCH v2 15/19] KVM: arm64: nv: timers: Add a per-timer, per-vcpu offset Marc Zyngier
2023-03-13 12:48 ` [PATCH v2 16/19] KVM: arm64: nv: timers: Support hyp timer emulation Marc Zyngier
2023-03-13 12:48 ` [PATCH v2 17/19] KVM: arm64: selftests: Add physical timer registers to the sysreg list Marc Zyngier
2023-03-13 12:48 ` [PATCH v2 18/19] KVM: arm64: selftests: Augment existing timer test to handle variable offset Marc Zyngier
2023-03-13 12:48 ` [PATCH v2 19/19] KVM: arm64: selftests: Deal with spurious timer interrupts Marc Zyngier
2023-03-23 22:19 ` [PATCH v2 00/19] KVM: arm64: Rework timer offsetting for fun and profit Colton Lewis
2023-03-23 22:54 ` Marc Zyngier
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