From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pf0-f171.google.com (mail-pf0-f171.google.com [209.85.192.171]) by dpdk.org (Postfix) with ESMTP id B537CDE6 for ; Thu, 17 Dec 2015 09:17:57 +0100 (CET) Received: by mail-pf0-f171.google.com with SMTP id 68so26792709pfc.1 for ; Thu, 17 Dec 2015 00:17:57 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=mvista-com.20150623.gappssmtp.com; s=20150623; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc:content-type; bh=K/6udqaENii8267kvNdZq55MaSPEU91aXrNxiooUcnc=; b=JjGWoA1vqW/KMr+zLNIhYrcFhn78x/86A9HtJOAjKvmwHBzyEvkOi9/YXlswWCjvSZ LIbMpbqjDIiyiGgQTMcFbCg1BZnYGVHSWjXqHsoqoqDqrKYPiDZ8FbEKCqF9wqKW7iU1 +ieB3pTIQEwC0M4FqwSHdtouVH0t1u8uNZV8IFPUEyhX+cDTS5tuvHkzi5DrQwDEPoZW ezEzXnWQ8HG7+Xt0EjIb6QOZOKRWEiZP/q1mV4VzdQiRImYorcebzEI0J59HCQs6Tf2O tG5TxM2skrkjdBH0UisOReghJHmwMwgAR+z6con4S2fRbp0xh+fGsPzyvpu9PwU0venj G3Ag== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; 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charset=UTF-8 Cc: dev@dpdk.org Subject: Re: [dpdk-dev] [ [PATCH v2] 05/13] virtio: change io_base datatype from uint32_t to uint64_type X-BeenThere: dev@dpdk.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: patches and discussions about DPDK List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 17 Dec 2015 08:17:58 -0000 On Thu, Dec 17, 2015 at 12:49 PM, Yuanhan Liu wrote: > On Wed, Dec 16, 2015 at 08:35:58PM +0530, Santosh Shukla wrote: >> On Wed, Dec 16, 2015 at 8:28 PM, Yuanhan Liu >> wrote: >> > On Wed, Dec 16, 2015 at 08:09:40PM +0530, Santosh Shukla wrote: >> >> On Wed, Dec 16, 2015 at 7:53 PM, Yuanhan Liu >> >> wrote: >> >> > On Wed, Dec 16, 2015 at 07:31:57PM +0530, Santosh Shukla wrote: >> >> >> On Wed, Dec 16, 2015 at 7:18 PM, Yuanhan Liu >> >> >> wrote: >> >> >> > On Mon, Dec 14, 2015 at 06:30:24PM +0530, Santosh Shukla wrote: >> >> >> >> In x86 case io_base to store ioport address not more than 65535 ioports. i.e..0 >> >> >> >> to ffff but in non-x86 case in particular arm64 it need to store more than 32 >> >> >> >> bit address so changing io_base datatype from 32 to 64. >> >> >> >> >> >> >> >> Signed-off-by: Santosh Shukla >> >> >> >> --- >> >> >> >> drivers/net/virtio/virtio_ethdev.c | 2 +- >> >> >> >> drivers/net/virtio/virtio_pci.h | 4 ++-- >> >> >> >> 2 files changed, 3 insertions(+), 3 deletions(-) >> >> >> >> >> >> >> >> diff --git a/drivers/net/virtio/virtio_ethdev.c b/drivers/net/virtio/virtio_ethdev.c >> >> >> >> index d928339..620e0d4 100644 >> >> >> >> --- a/drivers/net/virtio/virtio_ethdev.c >> >> >> >> +++ b/drivers/net/virtio/virtio_ethdev.c >> >> >> >> @@ -1291,7 +1291,7 @@ eth_virtio_dev_init(struct rte_eth_dev *eth_dev) >> >> >> >> return -1; >> >> >> >> >> >> >> >> hw->use_msix = virtio_has_msix(&pci_dev->addr); >> >> >> >> - hw->io_base = (uint32_t)(uintptr_t)pci_dev->mem_resource[0].addr; >> >> >> >> + hw->io_base = (uint64_t)(uintptr_t)pci_dev->mem_resource[0].addr; >> >> >> > >> >> >> > I'd suggest to move the io_base assignment (and cast) into virtio_ioport_init() >> >> >> > so that we could do the correct cast there, say cast it to uint32_t for >> >> >> > X86, and uint64_t for others. >> >> >> > >> >> >> >> >> >> Ok. >> >> >> >> >> >> This was deliberately done considering your 1.0 virtio spec patch do >> >> >> care for uint64_t types and in arm64 case, If I plan to use those >> >> >> future patches, IMO it make more sense to me keep it in uint64_t way; >> >> > >> >> > I did different cast, 32 bit for legacy virtio pci device, and 64 bit >> >> > for modern virtio pci device. >> >> > >> >> >> Also in x86 case max address could of type 0x1000-101f and so forth; >> >> >> changing data-type to uint64_t default wont effect such address, >> >> >> right? >> >> > >> >> > Right, but what's the harm of doing the right cast? :) >> >> > >> >> >> >> Agree. >> >> >> >> >> And hw->io_base by looking at virtio_pci.h function like >> >> >> inb/outb etc.. takes io_base address as unsigned long types which is >> >> >> arch dependent; i.e.. 4 byte for 32 bit and 8 for 64 bit so the lower >> >> >> level rd/wr apis are taking care of data-types accordingly. >> >> > >> >> > Didn't get it. inb/outb takes "unsigned short" arguments, but not >> >> > "unsigned long". >> >> > >> >> >> >> sys/io.h in x86 case using unsigned short int types.. >> >> >> >> include/asm-generic/io.h for arm64 using it unsigned long (from linux >> >> header files) >> >> >> >> In such case keeping >> >> #define VIRTIO_PCI_REG_ADDR(hw, reg) \ >> >> (unsigned short)((hw)->io_base + (reg)) >> >> >> >> would be x86 specific and what I thought and used in this patch is >> >> >> >> #define VIRTIO_PCI_REG_ADDR(hw, reg) \ >> >> (unsigned long)((hw)->io_base + (reg)) >> >> >> >> to avoid ifdef ARM or non-x86..clutter, I know data-type is not right >> >> fit for x86 sys/io.h but considering possible address inside >> >> hw->io_base, wont effect functionality and performance my any mean. >> >> That is why at virtio_ethdev_init() i choose to keep it in hw->io_base >> >> = (uint64_t) types. >> >> >> >> Otherwise I'll have to duplicate VIRTIO_PCI_REG_XXX definition for >> >> non-x86 case, Pl. suggest better alternative. Thanks >> > >> > >> > My understanding is that if you have done the right cast in the first >> > time (at the io_base assignment), casting from a short type to a longer >> > type will not matter: the upper bits will be filled with zero. >> > >> > So, I guess we are fine here. I'm thinking that the extra cast in >> > VIRTIO_PCI_REG_ADDR() is not necessary, as C will do the right >> > cast for different inb(), say cast it to "unsigned short" for x86, >> > and "unsigned long" for your arm implementation. The same to >> > other io helpers. >> > >> >> so to summarize and correct me if i misunderstood, >> keep hw->io_base = (uint64_t) > > I still want a different explicit cast for x86 and non-x86. And > actually, we should cast it to (unsigned short) but not (uint32_t) > for x86, don't we? > > On the other hand, we may cast it to uint64_t unconditionally, > and then have an explicit sanity check for io_base for x86, say > > if ((unsigned short)hw->io_base != hw->io_base) { > PMD_INIT_LOG(ERR, "invalid io port: %"PRIx64, ...); > return -1; > } > > It's better than the (unsigned short) cast, as the later simply hides > issue when something went wrong, though it's not rare. > > What do you think of that? > Liked the later part which is casting uint64_t unconditionally and keeping a (unsigned short) check for x86 case. We'll do it in v3. >> and remove extra cast {i.e.. (unsigned short) for x86 or (unsigned >> long) for non-x86/arm64 case} in VIRTIO_PCI_REG_ADDR(). > > Technically speaking, yes, we don't need this kind of cast. > Ok. > --yliu