From: Anup Patel <anup@brainfault.org>
To: Paolo Bonzini <pbonzini@redhat.com>
Cc: Damien Le Moal <Damien.LeMoal@wdc.com>,
Palmer Dabbelt <palmer@sifive.com>,
Daniel Lezcano <daniel.lezcano@linaro.org>,
"kvm@vger.kernel.org" <kvm@vger.kernel.org>,
Radim K <rkrcmar@redhat.com>, Anup Patel <Anup.Patel@wdc.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Christoph Hellwig <hch@infradead.org>,
Atish Patra <Atish.Patra@wdc.com>,
Alexander Graf <graf@amazon.com>,
Paul Walmsley <paul.walmsley@sifive.com>,
Alistair Francis <Alistair.Francis@wdc.com>,
Thomas Gleixner <tglx@linutronix.de>,
"linux-riscv@lists.infradead.org"
<linux-riscv@lists.infradead.org>
Subject: Re: [PATCH v9 20/22] RISC-V: KVM: Fix race-condition in kvm_riscv_vcpu_sync_interrupts()
Date: Tue, 22 Oct 2019 10:37:43 +0530 [thread overview]
Message-ID: <CAAhSdy33b=EcNnNP80dNqAEpSOErfXenNXHD0GhC4yYPB7L3Ow@mail.gmail.com> (raw)
In-Reply-To: <1d2e9514-235e-183e-b4fc-d3becc9ce471@redhat.com>
On Mon, Oct 21, 2019 at 10:57 PM Paolo Bonzini <pbonzini@redhat.com> wrote:
>
> On 16/10/19 18:12, Anup Patel wrote:
> > + /* Read current VSIP and VSIE CSRs */
> > + vsip = csr_read(CSR_VSIP);
> > + csr->vsie = csr_read(CSR_VSIE);
> > +
> > + /* Sync-up VSIP.SSIP bit changes does by Guest */
> > + if ((csr->vsip ^ vsip) & (1UL << IRQ_S_SOFT)) {
> > + if (!test_and_set_bit(IRQ_S_SOFT, &v->irqs_pending_mask)) {
> > + if (vsip & (1UL << IRQ_S_SOFT))
> > + set_bit(IRQ_S_SOFT, &v->irqs_pending);
> > + else
> > + clear_bit(IRQ_S_SOFT, &v->irqs_pending);
> > + }
>
> Looks good, but I wonder if this could just be "csr->vsip =
> csr_read(CSR_VSIP)", which will be fixed up by flush_interrupts on the
> next entry.
It's not just "csr->vsip = csr_read(CSR_VSIP" because "irqs_pending"
bitmap has to be in-sync with Guest updates to VSIP because WFI
trap-n-emulate will check for pending interrupts which in-turn checks
"irqs_pending" bitmap.
Regards,
Anup
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next prev parent reply other threads:[~2019-10-22 5:08 UTC|newest]
Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-10-16 16:08 [PATCH v9 00/22] KVM RISC-V Support Anup Patel
2019-10-16 16:08 ` [PATCH v9 01/22] RISC-V: Add bitmap reprensenting ISA features common across CPUs Anup Patel
2019-10-17 8:48 ` Anup Patel
2019-10-25 23:30 ` Paul Walmsley
2019-10-16 16:08 ` [PATCH v9 02/22] RISC-V: Add hypervisor extension related CSR defines Anup Patel
2019-10-16 16:08 ` [PATCH v9 03/22] RISC-V: Add initial skeletal KVM support Anup Patel
2019-11-20 8:04 ` Paul Walmsley
2019-10-16 16:08 ` [PATCH v9 04/22] RISC-V: KVM: Implement VCPU create, init and destroy functions Anup Patel
2019-10-16 16:09 ` [PATCH v9 05/22] RISC-V: KVM: Implement VCPU interrupts and requests handling Anup Patel
2019-10-16 16:09 ` [PATCH v9 06/22] RISC-V: KVM: Implement KVM_GET_ONE_REG/KVM_SET_ONE_REG ioctls Anup Patel
2019-10-16 16:09 ` [PATCH v9 07/22] RISC-V: KVM: Implement VCPU world-switch Anup Patel
2019-10-16 16:09 ` [PATCH v9 08/22] RISC-V: KVM: Handle MMIO exits for VCPU Anup Patel
2019-10-16 16:10 ` [PATCH v9 09/22] RISC-V: KVM: Handle WFI " Anup Patel
2019-10-16 16:10 ` [PATCH v9 10/22] RISC-V: KVM: Implement VMID allocator Anup Patel
2019-10-16 16:10 ` [PATCH v9 11/22] RISC-V: KVM: Implement stage2 page table programming Anup Patel
2019-10-16 16:10 ` [PATCH v9 12/22] RISC-V: KVM: Implement MMU notifiers Anup Patel
2019-10-16 16:10 ` [PATCH v9 13/22] RISC-V: KVM: Add timer functionality Anup Patel
2019-12-04 16:08 ` Daniel Lezcano
2019-10-16 16:10 ` [PATCH v9 14/22] RISC-V: KVM: FP lazy save/restore Anup Patel
2019-10-16 16:11 ` [PATCH v9 15/22] RISC-V: KVM: Implement ONE REG interface for FP registers Anup Patel
2019-10-16 16:11 ` [PATCH v9 16/22] RISC-V: KVM: Add SBI v0.1 support Anup Patel
2019-10-16 16:11 ` [PATCH v9 17/22] RISC-V: KVM: Forward unhandled SBI calls to userspace Anup Patel
2019-10-16 16:11 ` [PATCH v9 18/22] RISC-V: KVM: Simplify stage2 page table programming Anup Patel
2019-10-21 17:31 ` Paolo Bonzini
2019-10-22 5:12 ` Anup Patel
2019-10-16 16:12 ` [PATCH v9 19/22] RISC-V: KVM: Remove per-CPU vsip_shadow variable Anup Patel
2019-10-21 17:28 ` Paolo Bonzini
2019-10-22 5:09 ` Anup Patel
2019-10-16 16:12 ` [PATCH v9 20/22] RISC-V: KVM: Fix race-condition in kvm_riscv_vcpu_sync_interrupts() Anup Patel
2019-10-21 17:27 ` Paolo Bonzini
2019-10-22 5:07 ` Anup Patel [this message]
2019-10-16 16:12 ` [PATCH v9 21/22] RISC-V: KVM: Document RISC-V specific parts of KVM API Anup Patel
2019-10-16 16:12 ` [PATCH v9 22/22] RISC-V: KVM: Add MAINTAINERS entry Anup Patel
2019-10-25 23:10 ` [PATCH v9 00/22] KVM RISC-V Support Paul Walmsley
2019-10-26 3:22 ` Anup Patel
2019-10-26 5:33 ` Christoph Hellwig
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