From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mailman by lists.gnu.org with tmda-scanned (Exim 4.43) id 1MxiZ9-0003Nk-3R for qemu-devel@nongnu.org; Tue, 13 Oct 2009 10:41:31 -0400 Received: from exim by lists.gnu.org with spam-scanned (Exim 4.43) id 1MxiZ4-0003HR-5Q for qemu-devel@nongnu.org; Tue, 13 Oct 2009 10:41:30 -0400 Received: from [199.232.76.173] (port=58288 helo=monty-python.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1MxiZ3-0003HE-Ts for qemu-devel@nongnu.org; Tue, 13 Oct 2009 10:41:26 -0400 Received: from mx1.redhat.com ([209.132.183.28]:11633) by monty-python.gnu.org with esmtp (Exim 4.60) (envelope-from ) id 1MxiZ3-0005I9-Bg for qemu-devel@nongnu.org; Tue, 13 Oct 2009 10:41:25 -0400 Date: Tue, 13 Oct 2009 16:39:15 +0200 From: "Michael S. Tsirkin" Message-ID: <20091013143914.GB17895@redhat.com> References: <1255069742-15724-1-git-send-email-yamahata@valinux.co.jp> <1255069742-15724-16-git-send-email-yamahata@valinux.co.jp> <20091011104312.GA15590@redhat.com> <20091013133133.GE2306%yamahata@valinux.co.jp> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20091013133133.GE2306%yamahata@valinux.co.jp> Subject: [Qemu-devel] Re: [PATCH V5 15/29] pci: typedef pcibus_t as uint64_t instead of uint32_t. List-Id: qemu-devel.nongnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Isaku Yamahata Cc: qemu-devel@nongnu.org On Tue, Oct 13, 2009 at 10:31:33PM +0900, Isaku Yamahata wrote: > On Sun, Oct 11, 2009 at 12:43:12PM +0200, Michael S. Tsirkin wrote: > > On Fri, Oct 09, 2009 at 03:28:48PM +0900, Isaku Yamahata wrote: > > > This patch is preliminary for 64bit bar. > > > For 64bit bar support, change pcibus_t which represents > > > pci bus addr/size from uint32_t to uint64_t. > > > And also change FMT_pcibus for printf. > > > > > > In pci_update_mapping() checks 32bit overflow. > > > So the check must be updated too. > > > > > > Signed-off-by: Isaku Yamahata > > > > That's all fine, but if you look at users implementing > > map io, they do: cpu_register_physical_memory() > > on the address they are given. And if target_phys_addr_t is 32 bit, > > this will silently truncate the address. > > > > So I would like to understand how this will all > > work on 32 bit systems. > > The case is > . BAR is memory 64bit and > . target_phys_addr_t is 32bit and > . bar is set to >4G. > Hmm, the case isn't checked. > > It would be checked by > - last_addr <= new_addr > + (target_phys_addr_t)last_addr <= new_addr That's pretty tricky. Can we just convert everything into 64 bit unconditionally and just do simple range checks? > > I'll fix it with comments added. Nice catch. Is this the right thing to do though? I think 32 bit CPU might address something like 64G memory of highmem support, so a 64 bit value might actually be valid. Let's step back and understand what the motivation is? Maybe declaring all bars as 32 bit for 32 bit targets is enough? > > > > > > --- > > > hw/pci.c | 9 ++++++++- > > > hw/pci.h | 4 ++-- > > > 2 files changed, 10 insertions(+), 3 deletions(-) > > > > > > diff --git a/hw/pci.c b/hw/pci.c > > > index c0ae66a..e7f8fb4 100644 > > > --- a/hw/pci.c > > > +++ b/hw/pci.c > > > @@ -524,7 +524,14 @@ static void pci_update_mappings(PCIDevice *d) > > > mappings, we handle specific values as invalid > > > mappings. */ > > > if (last_addr <= new_addr || new_addr == 0 || > > > - last_addr == PCI_BAR_UNMAPPED) { > > > + last_addr == PCI_BAR_UNMAPPED || > > > + > > > + /* Now pcibus_t is 64bit. > > > + * Check if 32 bit BAR wrap around explicitly. > > > + * Without this, PC ide doesn't work well. > > > + * TODO: remove this work around. > > > + */ > > > + last_addr >= UINT32_MAX) { > > > new_addr = PCI_BAR_UNMAPPED; > > > } > > > } else { > > > diff --git a/hw/pci.h b/hw/pci.h > > > index 8a187c2..8fbd45e 100644 > > > --- a/hw/pci.h > > > +++ b/hw/pci.h > > > @@ -71,8 +71,8 @@ extern target_phys_addr_t pci_mem_base; > > > #define PCI_DEVICE_ID_VIRTIO_BALLOON 0x1002 > > > #define PCI_DEVICE_ID_VIRTIO_CONSOLE 0x1003 > > > > > > -typedef uint32_t pcibus_t; > > > -#define FMT_PCIBUS PRIx32 > > > +typedef uint64_t pcibus_t; > > > +#define FMT_PCIBUS PRIx64 > > > > > > typedef void PCIConfigWriteFunc(PCIDevice *pci_dev, > > > uint32_t address, uint32_t data, int len); > > > > -- > yamahata