Am 22.02.2013 16:37, schrieb Hao, Xudong: >> -----Original Message----- >> From: Jan Beulich [mailto:jbeul...@suse.com] >> Sent: Friday, February 22, 2013 5:04 PM >> To: Hao, Xudong >> Cc: stefano.stabell...@eu.citrix.com; Zhang, Xiantao; >> xen-de...@lists.xen.org; >> qemu-devel@nongnu.org; m...@redhat.com; aligu...@us.ibm.com >> Subject: Re: [Xen-devel] [PATCH] qemu: define a TOM register to report the >> base of PCI >> >>>>> On 22.02.13 at 04:23, Xudong Hao <xudong....@intel.com> wrote: >>> @@ -203,6 +251,16 @@ static int i440fx_initfn(PCIDevice *dev) >>> >>> d->dev.config[I440FX_SMRAM] = 0x02; >>> >>> + /* Emulate top of memory, here use 0xe0000000 as default val*/ >>> + if (xen_enabled()) { >>> + d->dev.config[I440FX_PCI_HOLE_BASE] = 0xf0; >>> + } else { >>> + d->dev.config[I440FX_PCI_HOLE_BASE] = 0xe0; >>> + } >>> + d->dev.config[I440FX_PCI_HOLE_BASE + 1] = 0x00; >>> + d->dev.config[I440FX_PCI_HOLE_BASE + 2] = 0x00; >>> + d->dev.config[I440FX_PCI_HOLE_BASE + 3] = 0x00; >>> + >>> cpu_smm_register(&i440fx_set_smm, d); >>> return 0; >>> } >> >> Isn't this the wrong way round (big endian, when it needs to be >> little)? >> > Jan, > > Here it should be little endian since the following config reading is little > endian, I'll correct it. Thanks your comments.
Your colleague David Woodhouse has just prepared some i440fx cleanups. Please use dev->config instead of the indirect d->dev.config. Given Jan's endianness comment, would alignment allow you to simply write as follows? uint32_t addr = xen_enabled() ? 0xe0000000 : 0xf0000000; *(uint32_t *)&dev->config[I440FX_PCI_HOLE_BASE] = cpu_to_le32(addr); Then the byte-swapping would be explicit and the address in one piece grep'able. Alternatively: cpu_to_le32s(&addr); for (i = 0; i < 4; i++) { dev->config[... + i] = ((uint8_t *)&addr)[i]; } Anyway, please use "piix: " in the subject rather than "qemu: " if this is supposed to go into upstream qemu.git. Regards, Andreas -- SUSE LINUX Products GmbH, Maxfeldstr. 5, 90409 Nürnberg, Germany GF: Jeff Hawn, Jennifer Guild, Felix Imendörffer; HRB 16746 AG Nürnberg