[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] Xen, MCFG acpi table and E820 address map
>>> On 04.09.13 at 18:24, Gordan Bobic <gordan@xxxxxxxxxx> wrote: > On Wed, 4 Sep 2013 16:14:55 +0000, Santosh Jodh > <Santosh.Jodh@xxxxxxxxxx> wrote: >> -----Original Message----- >> From: Konrad Rzeszutek Wilk [mailto:konrad.wilk@xxxxxxxxxx] >> Sent: Wednesday, September 04, 2013 8:01 AM >> To: Jan Beulich >> Cc: Santosh Jodh; David Vrabel; xen-devel; Boris Ostrovsky >> Subject: Re: [Xen-devel] Xen, MCFG acpi table and E820 address map >> >> On Wed, Sep 04, 2013 at 10:16:26AM +0100, Jan Beulich wrote: >>> >>> On 04.09.13 at 03:13, Santosh Jodh <Santosh.Jodh@xxxxxxxxxx> >>> wrote: >>> > Xen will use information from MCFG acpi table to access PCIe >>> > extended configuration space. However, Xen validates MCFG table by >>> > making sure that the addresses specified in the MCFG table is >>> > correctly marked as reserved in the E820 address map. If it is >>> not, >>> > the MCFG table is ignored - thereby preventing Xen from accessing >>> PCIe extended configuration space. >>> > >>> > I recently came across a workstation class system that supports >>> > VT-d. This system BIOS has a valid MCFG table. The BIOS does NOT >>> > report the MCFG addresses as reserved in the E820 address map. >>> > However, the addresses ARE claimed as reserved via the ACPI >>> > motherboard resource devnode (PNP0C01) mechanism. >> >> Could you tell me what machine this is? It would be good to know to >> develop a patch against it. >> [Santosh Jodh] Unfortunately, this is a new platform I cannot >> disclose much about. > > If this is pre-release/experimental hardware, isn't the > right thing to do to talk to the manufacturer and get them > to fix the BIOS so it exposes the correct e820 map in the > first place? No. As said in an earlier reply, this is legitimate behavior that - as shown - Linux can deal with. It's just the lack of the use of the intended interface by the pv-ops kernel that gets in the way here. In fact I have at least one system that also exhibits such behavior; whether that's also a pre-release specific situation (most of the systems I use for regular testing found their way here by other than purchase) I can't tell, but it at least got me to spot the Linux side solution and integrate it with Xen. Jan _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx http://lists.xen.org/xen-devel
|
Lists.xenproject.org is hosted with RackSpace, monitoring our |