From: Yuanhan Liu <yuanhan.liu@linux.intel.com>
To: Santosh Shukla <sshukla@mvista.com>
Cc: dev@dpdk.org
Subject: Re: [dpdk-dev] [ [PATCH v2] 05/13] virtio: change io_base datatype from uint32_t to uint64_type
Date: Thu, 17 Dec 2015 15:19:27 +0800 [thread overview]
Message-ID: <20151217071927.GA29571@yliu-dev.sh.intel.com> (raw)
In-Reply-To: <CAAyOgsZ77+aEwNWRFb9Jg=HTa4BX=8eCJbnRqP_HMNdJ0fPW+w@mail.gmail.com>
On Wed, Dec 16, 2015 at 08:35:58PM +0530, Santosh Shukla wrote:
> On Wed, Dec 16, 2015 at 8:28 PM, Yuanhan Liu
> <yuanhan.liu@linux.intel.com> 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
> >> <yuanhan.liu@linux.intel.com> 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
> >> >> <yuanhan.liu@linux.intel.com> 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 <sshukla@mvista.com>
> >> >> >> ---
> >> >> >> 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?
> 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.
--yliu
next prev parent reply other threads:[~2015-12-17 7:19 UTC|newest]
Thread overview: 88+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-12-14 13:00 [dpdk-dev] [ [PATCH v2] 00/13] Add virtio support in arm/arm64 Santosh Shukla
2015-12-14 13:00 ` [dpdk-dev] [ [PATCH v2] 01/13] virtio: Introduce config RTE_VIRTIO_INC_VECTOR Santosh Shukla
2015-12-17 12:02 ` Santosh Shukla
2015-12-17 12:03 ` Thomas Monjalon
2015-12-17 12:18 ` Santosh Shukla
2015-12-17 23:24 ` Stephen Hemminger
2015-12-18 1:31 ` Yuanhan Liu
2015-12-18 9:52 ` Xie, Huawei
2015-12-18 10:41 ` Thomas Monjalon
2015-12-18 17:33 ` Stephen Hemminger
2015-12-18 18:11 ` Thomas Monjalon
2015-12-18 12:46 ` Santosh Shukla
2015-12-22 6:26 ` Yuanhan Liu
2015-12-14 13:00 ` [dpdk-dev] [ [PATCH v2] 02/13] config: i686: set RTE_VIRTIO_INC_VECTOR=n Santosh Shukla
2015-12-17 12:03 ` Santosh Shukla
2015-12-14 13:00 ` [dpdk-dev] [ [PATCH v2] 03/13] rte_io: armv7/v8: Introduce api to emulate x86-style of PCI/ISA ioport access Santosh Shukla
2015-12-14 14:25 ` Jerin Jacob
2015-12-14 16:29 ` Santosh Shukla
2015-12-14 13:00 ` [dpdk-dev] [ [PATCH v2] 04/13] virtio_pci: use rte_io.h for non-x86 arch Santosh Shukla
2015-12-14 14:28 ` Jerin Jacob
2015-12-14 15:29 ` Santosh Shukla
2015-12-14 13:00 ` [dpdk-dev] [ [PATCH v2] 05/13] virtio: change io_base datatype from uint32_t to uint64_type Santosh Shukla
2015-12-16 13:48 ` Yuanhan Liu
2015-12-16 14:01 ` Santosh Shukla
2015-12-16 14:23 ` Yuanhan Liu
2015-12-16 14:39 ` Santosh Shukla
2015-12-16 14:58 ` Yuanhan Liu
2015-12-16 15:05 ` Santosh Shukla
2015-12-17 7:19 ` Yuanhan Liu [this message]
2015-12-17 8:17 ` Santosh Shukla
2015-12-14 13:00 ` [dpdk-dev] [ [PATCH v2] 06/13] config: armv7/v8: Enable RTE_LIBRTE_VIRTIO_PMD Santosh Shukla
2015-12-14 14:31 ` Jerin Jacob
2015-12-14 16:16 ` Santosh Shukla
2015-12-15 5:36 ` Jianbo Liu
2015-12-14 13:00 ` [dpdk-dev] [ [PATCH v2] 07/13] linuxapp: eal: arm: Always return 0 for rte_eal_iopl_init() Santosh Shukla
2015-12-14 14:34 ` Jan Viktorin
2015-12-14 15:04 ` Santosh Shukla
2015-12-14 14:37 ` Jerin Jacob
2015-12-14 15:24 ` Santosh Shukla
2015-12-14 15:56 ` Jerin Jacob
2015-12-14 16:13 ` Santosh Shukla
2015-12-14 13:00 ` [dpdk-dev] [ [PATCH v2] 08/13] rte_io: x86: Remove sys/io.h ifdef x86 clutter Santosh Shukla
2015-12-14 13:00 ` [dpdk-dev] [ [PATCH v2] 09/13] igb_uio: ioport: map iopci region for armv7/v8 Santosh Shukla
2015-12-14 13:00 ` [dpdk-dev] [ [PATCH v2] 10/13] include/exec-env: ioport: add rte_virt_ioport header file Santosh Shukla
2015-12-14 14:43 ` Jerin Jacob
2015-12-14 16:17 ` Santosh Shukla
2015-12-14 13:00 ` [dpdk-dev] [ [PATCH v2] 11/13] virtio_ioport: armv7/v8: mmap virtio iopci bar region Santosh Shukla
2015-12-16 13:29 ` Yuanhan Liu
2015-12-16 14:20 ` Santosh Shukla
2015-12-16 14:37 ` Yuanhan Liu
2015-12-16 14:40 ` Santosh Shukla
2015-12-14 13:00 ` [dpdk-dev] [ [PATCH v2] 12/13] virtio_ethdev: use virtio_ioport api at device init/close Santosh Shukla
2015-12-14 13:00 ` [dpdk-dev] [ [PATCH v2] 13/13] virtio_ethdev : fix format specifier error for 64bit addr case Santosh Shukla
2015-12-14 14:31 ` [dpdk-dev] [ [PATCH v2] 00/13] Add virtio support in arm/arm64 Jan Viktorin
2015-12-14 16:09 ` Santosh Shukla
2015-12-16 7:48 ` Santosh Shukla
2015-12-16 8:47 ` David Marchand
2015-12-16 11:43 ` Santosh Shukla
2015-12-16 12:31 ` [dpdk-dev] [PATCH] eal: map io resources for non x86 architectures David Marchand
2015-12-16 12:48 ` Yuanhan Liu
2015-12-16 13:34 ` David Marchand
2015-12-16 13:42 ` Yuanhan Liu
2015-12-16 13:51 ` Santosh Shukla
2015-12-17 9:38 ` Yuanhan Liu
2015-12-17 10:01 ` Santosh Shukla
2015-12-17 10:02 ` Santosh Shukla
2015-12-17 10:07 ` Santosh Shukla
2015-12-17 10:14 ` Thomas Monjalon
2015-12-17 10:21 ` Santosh Shukla
2015-12-17 10:33 ` Thomas Monjalon
2015-12-17 11:22 ` Santosh Shukla
2015-12-18 5:30 ` Yuanhan Liu
2015-12-18 6:34 ` Jerin Jacob
2015-12-18 7:55 ` Yuanhan Liu
2015-12-18 9:37 ` Thomas Monjalon
2015-12-18 7:54 ` Santosh Shukla
2015-12-18 8:21 ` Yuanhan Liu
2015-12-18 12:55 ` Santosh Shukla
2015-12-29 5:56 ` Santosh Shukla
2015-12-29 9:56 ` Burakov, Anatoly
2015-12-29 10:47 ` Santosh Shukla
2015-12-29 11:06 ` Burakov, Anatoly
2015-12-29 12:23 ` Santosh Shukla
2015-12-29 14:04 ` Alex Williamson
2015-12-29 14:51 ` Santosh Shukla
2015-12-31 14:27 ` Santosh Shukla
2015-12-16 13:15 ` Bruce Richardson
2015-12-16 13:29 ` David Marchand
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