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[91.219.240.2]) by smtp.gmail.com with ESMTPSA id hf15-20020a1709072c4f00b006f3ef214e4asm1940876ejc.176.2022.05.06.07.13.57 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 06 May 2022 07:13:58 -0700 (PDT) From: Vitaly Kuznetsov To: vdasa@vmware.com Cc: pv-drivers@vmware.com, linux-kernel-review@vmware.com, Cyprien Laplace , Vishnu Dasa , Bryan Tan , gregkh@linuxfoundation.org, linux-kernel@vger.kernel.org, virtualization@lists.linux-foundation.org, linux-arm-kernel@lists.infradead.org Subject: Re: [PATCH] VMCI: Add support for ARM64 In-Reply-To: <20220414193316.14356-1-vdasa@vmware.com> References: <20220414193316.14356-1-vdasa@vmware.com> Date: Fri, 06 May 2022 16:13:57 +0200 Message-ID: <87levezr2y.fsf@redhat.com> MIME-Version: 1.0 Content-Type: text/plain Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org vdasa@vmware.com writes: > From: Vishnu Dasa > > Add support for ARM64 architecture so that the driver can now be built > and VMCI device can be used. > > Update Kconfig file to allow the driver to be built on ARM64 as well. > Fail vmci_guest_probe_device() on ARM64 if the device does not support > MMIO register access. Lastly, add virtualization specific barriers > which map to actual memory barrier instructions on ARM64, because it > is required in case of ARM64 for queuepair (de)queuing. > FWIW, it seems you're doing three things at once, better split this into a 3-patch series. > Reviewed-by: Bryan Tan > Reviewed-by: Cyprien Laplace > Signed-off-by: Vishnu Dasa > --- > drivers/misc/vmw_vmci/Kconfig | 2 +- > drivers/misc/vmw_vmci/vmci_guest.c | 4 ++++ > drivers/misc/vmw_vmci/vmci_queue_pair.c | 12 ++++++++++++ > 3 files changed, 17 insertions(+), 1 deletion(-) > > diff --git a/drivers/misc/vmw_vmci/Kconfig b/drivers/misc/vmw_vmci/Kconfig > index 605794aadf11..b6d4d7fd686a 100644 > --- a/drivers/misc/vmw_vmci/Kconfig > +++ b/drivers/misc/vmw_vmci/Kconfig > @@ -5,7 +5,7 @@ > > config VMWARE_VMCI > tristate "VMware VMCI Driver" > - depends on X86 && PCI > + depends on (X86 || ARM64) && !CPU_BIG_ENDIAN && PCI > help > This is VMware's Virtual Machine Communication Interface. It enables > high-speed communication between host and guest in a virtual > diff --git a/drivers/misc/vmw_vmci/vmci_guest.c b/drivers/misc/vmw_vmci/vmci_guest.c > index 57a6157209a1..aa7b05de97dd 100644 > --- a/drivers/misc/vmw_vmci/vmci_guest.c > +++ b/drivers/misc/vmw_vmci/vmci_guest.c > @@ -614,6 +614,10 @@ static int vmci_guest_probe_device(struct pci_dev *pdev, > } > > if (!mmio_base) { > + if (IS_ENABLED(CONFIG_ARM64)) { > + dev_err(&pdev->dev, "MMIO base is invalid\n"); > + return -ENXIO; > + } > error = pcim_iomap_regions(pdev, BIT(0), KBUILD_MODNAME); > if (error) { > dev_err(&pdev->dev, "Failed to reserve/map IO regions\n"); > diff --git a/drivers/misc/vmw_vmci/vmci_queue_pair.c b/drivers/misc/vmw_vmci/vmci_queue_pair.c > index 94ebf7f3fd58..8f2de1893245 100644 > --- a/drivers/misc/vmw_vmci/vmci_queue_pair.c > +++ b/drivers/misc/vmw_vmci/vmci_queue_pair.c > @@ -2577,6 +2577,12 @@ static ssize_t qp_enqueue_locked(struct vmci_queue *produce_q, > if (result < VMCI_SUCCESS) > return result; > > + /* > + * This virt_wmb() ensures that data written to the queue > + * is observable before the new producer_tail is. > + */ > + virt_wmb(); > + > vmci_q_header_add_producer_tail(produce_q->q_header, written, > produce_q_size); > return written; > @@ -2620,6 +2626,12 @@ static ssize_t qp_dequeue_locked(struct vmci_queue *produce_q, > if (buf_ready < VMCI_SUCCESS) > return (ssize_t) buf_ready; > > + /* > + * This virt_rmb() ensures that data from the queue will be read > + * after we have determined how much is ready to be consumed. > + */ > + virt_rmb(); > + > read = (size_t) (buf_ready > buf_size ? buf_size : buf_ready); > head = vmci_q_header_consumer_head(produce_q->q_header); > if (likely(head + read < consume_q_size)) { -- Vitaly