From: Alexandru Elisei <alexandru.elisei@arm.com>
To: Marc Zyngier <marc.zyngier@arm.com>,
linux-arm-kernel@lists.infradead.org,
kvmarm@lists.cs.columbia.edu, kvm@vger.kernel.org
Cc: Andre Przywara <andre.przywara@arm.com>,
Dave Martin <Dave.Martin@arm.com>
Subject: Re: [PATCH 40/59] KVM: arm64: nv: Don't always start an S2 MMU search from the beginning
Date: Tue, 9 Jul 2019 10:59:03 +0100 [thread overview]
Message-ID: <ccb11c22-0aa9-7e6a-98b2-acdfa0603eb0@arm.com> (raw)
In-Reply-To: <20190621093843.220980-41-marc.zyngier@arm.com>
On 6/21/19 10:38 AM, Marc Zyngier wrote:
> Starting a S2 MMU search from the beginning all the time means that
> we're potentially nuking a useful context (like we'd potentially
> have on a !VHE KVM guest).
>
> Instead, let's always start the search from the point *after* the
> last allocated context. This should ensure that alternating between
> two EL1 contexts will not result in nuking the whole S2 each time.
>
> lookup_s2_mmu now has a chance to provide a hit.
>
> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
> ---
> arch/arm64/include/asm/kvm_host.h | 1 +
> arch/arm64/kvm/nested.c | 14 ++++++++++++--
> 2 files changed, 13 insertions(+), 2 deletions(-)
>
> diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
> index b71a7a237f95..b7c44adcdbf3 100644
> --- a/arch/arm64/include/asm/kvm_host.h
> +++ b/arch/arm64/include/asm/kvm_host.h
> @@ -123,6 +123,7 @@ struct kvm_arch {
> */
> struct kvm_s2_mmu *nested_mmus;
> size_t nested_mmus_size;
> + int nested_mmus_next;
For consistency, shouldn't nested_mmus_next be zero initialized in
kvm_init_nested (arch/arm64/kvm/nested.c), like nested_mmus and
nested_mmus_size? Not a big deal either way, since struct kvm is allocated using
vzalloc.
> really
> /* VTCR_EL2 value for this VM */
> u64 vtcr;
> diff --git a/arch/arm64/kvm/nested.c b/arch/arm64/kvm/nested.c
> index 09afafbdc8fe..214d59019935 100644
> --- a/arch/arm64/kvm/nested.c
> +++ b/arch/arm64/kvm/nested.c
> @@ -363,14 +363,24 @@ static struct kvm_s2_mmu *get_s2_mmu_nested(struct kvm_vcpu *vcpu)
> if (s2_mmu)
> goto out;
>
> - for (i = 0; i < kvm->arch.nested_mmus_size; i++) {
> - s2_mmu = &kvm->arch.nested_mmus[i];
> + /*
> + * Make sure we don't always search from the same point, or we
> + * will always reuse a potentially active context, leaving
> + * free contexts unused.
> + */
> + for (i = kvm->arch.nested_mmus_next;
> + i < (kvm->arch.nested_mmus_size + kvm->arch.nested_mmus_next);
> + i++) {
> + s2_mmu = &kvm->arch.nested_mmus[i % kvm->arch.nested_mmus_size];
>
> if (atomic_read(&s2_mmu->refcnt) == 0)
> break;
> }
> BUG_ON(atomic_read(&s2_mmu->refcnt)); /* We have struct MMUs to spare */
>
> + /* Set the scene for the next search */
> + kvm->arch.nested_mmus_next = (i + 1) % kvm->arch.nested_mmus_size;
> +
> if (kvm_s2_mmu_valid(s2_mmu)) {
> /* Clear the old state */
> kvm_unmap_stage2_range(s2_mmu, 0, kvm_phys_size(kvm));
next prev parent reply other threads:[~2019-07-09 9:59 UTC|newest]
Thread overview: 176+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-06-21 9:37 [PATCH 00/59] KVM: arm64: ARMv8.3 Nested Virtualization support Marc Zyngier
2019-06-21 9:37 ` [PATCH 01/59] KVM: arm64: Migrate _elx sysreg accessors to msr_s/mrs_s Marc Zyngier
2019-06-24 11:16 ` Dave Martin
2019-06-24 12:59 ` Alexandru Elisei
2019-07-03 12:32 ` Marc Zyngier
2019-06-21 9:37 ` [PATCH 02/59] KVM: arm64: Move __load_guest_stage2 to kvm_mmu.h Marc Zyngier
2019-06-24 11:19 ` Dave Martin
2019-07-03 9:30 ` Marc Zyngier
2019-07-03 16:13 ` Dave Martin
2019-06-21 9:37 ` [PATCH 03/59] arm64: Add ARM64_HAS_NESTED_VIRT cpufeature Marc Zyngier
2019-06-21 13:08 ` Julien Thierry
2019-06-21 13:22 ` Marc Zyngier
2019-06-21 13:44 ` Suzuki K Poulose
2019-06-24 11:24 ` Dave Martin
2019-06-21 9:37 ` [PATCH 04/59] KVM: arm64: nv: Introduce nested virtualization VCPU feature Marc Zyngier
2019-06-21 13:08 ` Julien Thierry
2019-06-24 11:28 ` Dave Martin
2019-07-03 11:53 ` Marc Zyngier
2019-07-03 16:27 ` Dave Martin
2019-06-24 11:43 ` Dave Martin
2019-07-03 11:56 ` Marc Zyngier
2019-07-03 16:24 ` Dave Martin
2019-06-21 9:37 ` [PATCH 05/59] KVM: arm64: nv: Reset VCPU to EL2 registers if VCPU nested virt is set Marc Zyngier
2019-06-24 10:19 ` Suzuki K Poulose
2019-06-24 11:38 ` Dave Martin
2019-06-21 9:37 ` [PATCH 06/59] KVM: arm64: nv: Allow userspace to set PSR_MODE_EL2x Marc Zyngier
2019-06-21 13:24 ` Julien Thierry
2019-06-21 13:50 ` Marc Zyngier
2019-06-24 12:48 ` Dave Martin
2019-07-03 9:21 ` Marc Zyngier
2019-07-04 10:00 ` Dave Martin
2019-06-21 9:37 ` [PATCH 07/59] KVM: arm64: nv: Add EL2 system registers to vcpu context Marc Zyngier
2019-06-24 12:54 ` Dave Martin
2019-07-03 12:20 ` Marc Zyngier
2019-07-03 16:31 ` Dave Martin
2019-06-24 15:47 ` Alexandru Elisei
2019-07-03 13:20 ` Marc Zyngier
2019-07-03 16:01 ` Marc Zyngier
2019-07-01 16:36 ` Suzuki K Poulose
2019-06-21 9:37 ` [PATCH 08/59] KVM: arm64: nv: Reset VMPIDR_EL2 and VPIDR_EL2 to sane values Marc Zyngier
2019-06-24 12:59 ` Dave Martin
2019-06-21 9:37 ` [PATCH 09/59] KVM: arm64: nv: Add nested virt VCPU primitives for vEL2 VCPU state Marc Zyngier
2019-06-24 13:08 ` Dave Martin
2019-06-21 9:37 ` [PATCH 10/59] KVM: arm64: nv: Support virtual EL2 exceptions Marc Zyngier
2019-07-08 13:56 ` Steven Price
2019-06-21 9:37 ` [PATCH 11/59] KVM: arm64: nv: Inject HVC exceptions to the virtual EL2 Marc Zyngier
2019-06-25 13:13 ` Alexandru Elisei
2019-07-03 14:16 ` Marc Zyngier
2019-07-30 14:08 ` Alexandru Elisei
2019-06-21 9:37 ` [PATCH 12/59] KVM: arm64: nv: Handle trapped ERET from " Marc Zyngier
2019-07-02 12:00 ` Alexandru Elisei
2019-06-21 9:37 ` [PATCH 13/59] KVM: arm64: nv: Handle virtual EL2 registers in vcpu_read/write_sys_reg() Marc Zyngier
2019-06-24 12:42 ` Julien Thierry
2019-06-25 14:02 ` Alexandru Elisei
2019-07-03 12:15 ` Marc Zyngier
2019-07-03 15:21 ` Julien Thierry
2019-06-25 15:18 ` Alexandru Elisei
2019-07-01 9:58 ` Alexandru Elisei
2019-07-03 15:59 ` Marc Zyngier
2019-07-03 16:32 ` Alexandru Elisei
2019-07-04 14:39 ` Marc Zyngier
2019-06-26 15:04 ` Alexandru Elisei
2019-07-04 15:05 ` Marc Zyngier
2019-07-01 12:10 ` Alexandru Elisei
2019-06-21 9:37 ` [PATCH 14/59] KVM: arm64: nv: Handle SPSR_EL2 specially Marc Zyngier
2019-06-21 9:37 ` [PATCH 15/59] KVM: arm64: nv: Refactor vcpu_{read,write}_sys_reg Marc Zyngier
2019-06-24 15:07 ` Julien Thierry
2019-07-03 13:09 ` Marc Zyngier
2019-06-27 9:21 ` Alexandru Elisei
2019-07-04 15:15 ` Marc Zyngier
2019-06-21 9:38 ` [PATCH 16/59] KVM: arm64: nv: Save/Restore vEL2 sysregs Marc Zyngier
2019-06-25 8:48 ` Julien Thierry
2019-07-03 13:42 ` Marc Zyngier
2019-07-01 12:09 ` Alexandru Elisei
2019-08-21 11:57 ` Alexandru Elisei
2019-06-21 9:38 ` [PATCH 17/59] KVM: arm64: nv: Emulate PSTATE.M for a guest hypervisor Marc Zyngier
2019-06-21 9:38 ` [PATCH 18/59] KVM: arm64: nv: Trap EL1 VM register accesses in virtual EL2 Marc Zyngier
2019-07-01 16:12 ` Alexandru Elisei
2019-06-21 9:38 ` [PATCH 19/59] KVM: arm64: nv: Trap SPSR_EL1, ELR_EL1 and VBAR_EL1 from " Marc Zyngier
2019-06-21 9:38 ` [PATCH 20/59] KVM: arm64: nv: Trap CPACR_EL1 access in " Marc Zyngier
2019-07-01 16:40 ` Alexandru Elisei
2019-06-21 9:38 ` [PATCH 21/59] KVM: arm64: nv: Set a handler for the system instruction traps Marc Zyngier
2019-06-25 12:55 ` Julien Thierry
2019-07-03 14:15 ` Marc Zyngier
2019-06-21 9:38 ` [PATCH 22/59] KVM: arm64: nv: Handle PSCI call via smc from the guest Marc Zyngier
2019-06-21 9:38 ` [PATCH 23/59] KVM: arm64: nv: Respect virtual HCR_EL2.TWX setting Marc Zyngier
2019-06-25 14:19 ` Julien Thierry
2019-07-02 12:54 ` Alexandru Elisei
2019-07-03 14:18 ` Marc Zyngier
2019-06-21 9:38 ` [PATCH 24/59] KVM: arm64: nv: Respect virtual CPTR_EL2.TFP setting Marc Zyngier
2019-06-21 9:38 ` [PATCH 25/59] KVM: arm64: nv: Don't expose SVE to nested guests Marc Zyngier
2019-06-21 9:38 ` [PATCH 26/59] KVM: arm64: nv: Respect the virtual HCR_EL2.NV bit setting Marc Zyngier
2019-06-26 5:31 ` Julien Thierry
2019-07-03 16:31 ` Marc Zyngier
2019-06-21 9:38 ` [PATCH 27/59] KVM: arm64: nv: Respect virtual HCR_EL2.TVM and TRVM settings Marc Zyngier
2019-06-26 6:55 ` Julien Thierry
2019-07-04 14:57 ` Marc Zyngier
2019-06-21 9:38 ` [PATCH 28/59] KVM: arm64: nv: Respect the virtual HCR_EL2.NV1 bit setting Marc Zyngier
2019-06-26 7:23 ` Julien Thierry
2019-07-02 16:32 ` Alexandru Elisei
2019-07-03 9:10 ` Alexandru Elisei
2019-06-21 9:38 ` [PATCH 29/59] KVM: arm64: nv: Emulate EL12 register accesses from the virtual EL2 Marc Zyngier
2019-07-03 9:16 ` Alexandru Elisei
2019-06-21 9:38 ` [PATCH 30/59] KVM: arm64: nv: Configure HCR_EL2 for nested virtualization Marc Zyngier
2019-06-21 9:38 ` [PATCH 31/59] KVM: arm64: nv: Only toggle cache for virtual EL2 when SCTLR_EL2 changes Marc Zyngier
2019-06-21 9:38 ` [PATCH 32/59] KVM: arm64: nv: Hide RAS from nested guests Marc Zyngier
2019-07-03 13:59 ` Alexandru Elisei
2019-06-21 9:38 ` [PATCH 33/59] KVM: arm64: nv: Pretend we only support larger-than-host page sizes Marc Zyngier
2019-07-03 14:13 ` Alexandru Elisei
2019-06-21 9:38 ` [PATCH 34/59] KVM: arm/arm64: nv: Factor out stage 2 page table data from struct kvm Marc Zyngier
2019-07-03 15:52 ` Alexandru Elisei
2019-06-21 9:38 ` [PATCH 35/59] KVM: arm/arm64: nv: Support multiple nested stage 2 mmu structures Marc Zyngier
2019-06-25 12:19 ` Alexandru Elisei
2019-07-03 13:47 ` Marc Zyngier
2019-06-27 13:15 ` Julien Thierry
2019-07-04 15:51 ` Alexandru Elisei
2020-01-05 11:35 ` Marc Zyngier
2020-01-06 16:31 ` Alexandru Elisei
2019-06-21 9:38 ` [PATCH 36/59] KVM: arm64: nv: Implement nested Stage-2 page table walk logic Marc Zyngier
2019-06-21 9:38 ` [PATCH 37/59] KVM: arm64: nv: Handle shadow stage 2 page faults Marc Zyngier
2019-07-05 14:28 ` Alexandru Elisei
2019-06-21 9:38 ` [PATCH 38/59] KVM: arm64: nv: Unmap/flush shadow stage 2 page tables Marc Zyngier
2019-07-01 8:03 ` Julien Thierry
2019-06-21 9:38 ` [PATCH 39/59] KVM: arm64: nv: Move last_vcpu_ran to be per s2 mmu Marc Zyngier
2019-07-01 9:10 ` Julien Thierry
2019-07-05 15:28 ` Alexandru Elisei
2019-06-21 9:38 ` [PATCH 40/59] KVM: arm64: nv: Don't always start an S2 MMU search from the beginning Marc Zyngier
2019-07-09 9:59 ` Alexandru Elisei [this message]
2019-06-21 9:38 ` [PATCH 41/59] KVM: arm64: nv: Introduce sys_reg_desc.forward_trap Marc Zyngier
2019-06-21 9:38 ` [PATCH 42/59] KVM: arm64: nv: Rework the system instruction emulation framework Marc Zyngier
2019-06-21 9:38 ` [PATCH 43/59] KVM: arm64: nv: Trap and emulate AT instructions from virtual EL2 Marc Zyngier
2019-07-01 15:45 ` Julien Thierry
2019-07-09 13:20 ` Alexandru Elisei
2019-07-18 12:13 ` Tomasz Nowicki
[not found] ` <6537c8d2-3bda-788e-8861-b70971a625cb@arm.com>
2019-07-18 12:59 ` Tomasz Nowicki
2019-07-24 10:25 ` Tomasz Nowicki
2019-07-24 12:39 ` Marc Zyngier
2019-07-24 13:56 ` Tomasz Nowicki
2019-06-21 9:38 ` [PATCH 44/59] KVM: arm64: nv: Trap and emulate TLBI " Marc Zyngier
2019-07-02 12:37 ` Julien Thierry
2019-07-10 10:15 ` Alexandru Elisei
2019-06-21 9:38 ` [PATCH 45/59] KVM: arm64: nv: Handle traps for timer _EL02 and _EL2 sysregs accessors Marc Zyngier
2019-06-21 9:38 ` [PATCH 46/59] KVM: arm64: nv: arch_timer: Support hyp timer emulation Marc Zyngier
2019-07-10 16:23 ` Alexandru Elisei
2019-06-21 9:38 ` [PATCH 47/59] KVM: arm64: nv: Propagate CNTVOFF_EL2 to the virtual EL1 timer Marc Zyngier
2019-08-08 9:34 ` Alexandru Elisei
2019-06-21 9:38 ` [PATCH 48/59] KVM: arm64: nv: Load timer before the GIC Marc Zyngier
2019-07-11 13:17 ` Alexandru Elisei
2019-06-21 9:38 ` [PATCH 49/59] KVM: arm64: nv: vgic-v3: Take cpu_if pointer directly instead of vcpu Marc Zyngier
2019-06-21 9:38 ` [PATCH 50/59] KVM: arm64: nv: Nested GICv3 Support Marc Zyngier
2019-07-16 11:41 ` Alexandru Elisei
2019-06-21 9:38 ` [PATCH 51/59] KVM: arm64: nv: vgic: Emulate the HW bit in software Marc Zyngier
2019-06-21 9:38 ` [PATCH 52/59] KVM: arm64: nv: vgic: Allow userland to set VGIC maintenance IRQ Marc Zyngier
2019-07-04 7:38 ` Julien Thierry
2019-07-04 9:01 ` Andre Przywara
2019-07-04 9:04 ` Julien Thierry
2019-06-21 9:38 ` [PATCH 53/59] KVM: arm64: nv: Implement maintenance interrupt forwarding Marc Zyngier
2019-07-04 8:06 ` Julien Thierry
2019-07-16 16:35 ` Alexandru Elisei
2019-06-21 9:38 ` [PATCH 54/59] KVM: arm64: nv: Add nested GICv3 tracepoints Marc Zyngier
2019-06-21 9:38 ` [PATCH 55/59] arm64: KVM: nv: Add handling of EL2-specific timer registers Marc Zyngier
2019-07-11 12:35 ` Alexandru Elisei
2019-07-17 10:19 ` Alexandru Elisei
2019-06-21 9:38 ` [PATCH 56/59] arm64: KVM: nv: Honor SCTLR_EL2.SPAN on entering vEL2 Marc Zyngier
2019-06-21 9:38 ` [PATCH 57/59] arm64: KVM: nv: Handle SCTLR_EL2 RES0/RES1 bits Marc Zyngier
2019-06-21 9:38 ` [PATCH 58/59] arm64: KVM: nv: Restrict S2 RD/WR permissions to match the guest's Marc Zyngier
2019-06-21 9:38 ` [PATCH 59/59] arm64: KVM: nv: Allow userspace to request KVM_ARM_VCPU_NESTED_VIRT Marc Zyngier
[not found] ` <CANW9uyssDm_0ysC_pnvhHRrnsmFZik+3_ENmFz7L2GCmtH09fw@mail.gmail.com>
2019-06-21 11:21 ` [PATCH 00/59] KVM: arm64: ARMv8.3 Nested Virtualization support Marc Zyngier
2019-08-02 10:11 ` Alexandru Elisei
2019-08-02 10:30 ` Andrew Jones
2019-08-09 10:01 ` Alexandru Elisei
2019-08-09 11:44 ` Andrew Jones
2019-08-09 12:00 ` Alexandru Elisei
2019-08-09 13:00 ` Andrew Jones
2019-08-22 11:57 ` Alexandru Elisei
2019-08-22 15:32 ` Alexandru Elisei
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