[libvirt] [PATCH] pci: Ignore 32-bit PCIe domains
Intel VMD creates secondary PCIe domain, where child devices in this domain are aggregated behind a single end point. Linux exposes these as special 32-bit domains, and devices in them are not individually assignable. This patch ignores devices in such domains as desired, and prevents logging excessive errors, like: internal error: dev->name buffer overflow: 10000:00:00.0 Cc: Jonathan Derrick <jonathan.derrick@intel.com> Signed-off-by: Keith Busch <keith.busch@intel.com> --- src/util/virpci.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/src/util/virpci.c b/src/util/virpci.c index 55e4c3e49..53a6f2e51 100644 --- a/src/util/virpci.c +++ b/src/util/virpci.c @@ -1762,6 +1762,13 @@ virPCIDeviceNew(unsigned int domain, char *vendor = NULL; char *product = NULL; + + /* Devices in a 32-bit domain are special. Currently applicable to Intel + * VMD PCIe, where individual devices are not individually assignable. + */ + if (domain > USHRT_MAX) + return NULL; + if (VIR_ALLOC(dev) < 0) return NULL; -- 2.14.3
On Fri, Mar 16, 2018 at 11:39:36AM -0600, Keith Busch wrote:
Intel VMD creates secondary PCIe domain, where child devices in this domain are aggregated behind a single end point. Linux exposes these as special 32-bit domains, and devices in them are not individually assignable.
IIUC, your patch is addressing a problem for machines with a specific Intel PCIe device type. Is this "domain >= USHRT_MAX" scenario specific to just this Intel PCIe device type, or will such a high domain number indicate the same semantics for devices from any vendor.
This patch ignores devices in such domains as desired, and prevents logging excessive errors, like:
internal error: dev->name buffer overflow: 10000:00:00.0
Cc: Jonathan Derrick <jonathan.derrick@intel.com> Signed-off-by: Keith Busch <keith.busch@intel.com> --- src/util/virpci.c | 7 +++++++ 1 file changed, 7 insertions(+)
diff --git a/src/util/virpci.c b/src/util/virpci.c index 55e4c3e49..53a6f2e51 100644 --- a/src/util/virpci.c +++ b/src/util/virpci.c @@ -1762,6 +1762,13 @@ virPCIDeviceNew(unsigned int domain, char *vendor = NULL; char *product = NULL;
+ + /* Devices in a 32-bit domain are special. Currently applicable to Intel + * VMD PCIe, where individual devices are not individually assignable. + */ + if (domain > USHRT_MAX) + return NULL; + if (VIR_ALLOC(dev) < 0) return NULL;
-- 2.14.3
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On Mon, Mar 19, 2018 at 12:21:35PM +0000, Daniel P. Berrangé wrote:
On Fri, Mar 16, 2018 at 11:39:36AM -0600, Keith Busch wrote:
Intel VMD creates secondary PCIe domain, where child devices in this domain are aggregated behind a single end point. Linux exposes these as special 32-bit domains, and devices in them are not individually assignable.
IIUC, your patch is addressing a problem for machines with a specific Intel PCIe device type.
Is this "domain >= USHRT_MAX" scenario specific to just this Intel PCIe device type, or will such a high domain number indicate the same semantics for devices from any vendor.
Yes, there is no other vendor exporting multiple PCI domains that isn't tied to a platform sepcific 16-bit PCI _SEG.
participants (2)
-
Daniel P. Berrangé -
Keith Busch