ALSA: intel8x0: improve virtual environment detection
Detection code improved by PCI SSID usage. VM optimization
now enabled only for known devcices (skip host devices forwarded
to VM by VT-d or same kind of technology).
For debug/troubleshooting purposes optimization can be
forced (on/off) by module parameter: "inside_vm" (boolean).
Known devices (PCI SSID):
1af4:1100: Reserved for KVM devices. Note this is not yet
implemented for KVM's ICH/AC'97 emulation.
1ab8:xxxx: Parallels ICH/AC'97 emulated sound.
[ fixed a minor coding-style issue by tiwai]
Signed-off-by: Konstantin Ozerkov <kozerkov@parallels.com>
Signed-off-by: Denis V. Lunev <den@openvz.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
diff --git a/sound/pci/intel8x0.c b/sound/pci/intel8x0.c
index 2d4bb4c..11718b49 100644
--- a/sound/pci/intel8x0.c
+++ b/sound/pci/intel8x0.c
@@ -2937,20 +2937,41 @@
ICH_PCR, ICH_SCR, ICH_SIS_TCR
};
-static int __devinit snd_intel8x0_inside_vm(void)
+static int __devinit snd_intel8x0_inside_vm(struct pci_dev *pci)
{
- int result = inside_vm;
+ int result = inside_vm;
+ char *msg = NULL;
- if (result < 0) {
- /* detect KVM and Parallels virtual environments */
- result = kvm_para_available();
-#if defined(__i386__) || defined(__x86_64__)
- result = result || boot_cpu_has(X86_FEATURE_HYPERVISOR);
-#endif
+ /* check module parameter first (override detection) */
+ if (result >= 0) {
+ msg = result ? "enable (forced) VM" : "disable (forced) VM";
+ goto fini;
}
- if (result)
- printk(KERN_INFO "intel8x0: enable KVM optimization\n");
+ /* detect KVM and Parallels virtual environments */
+ result = kvm_para_available();
+#ifdef X86_FEATURE_HYPERVISOR
+ result = result || boot_cpu_has(X86_FEATURE_HYPERVISOR);
+#endif
+ if (!result)
+ goto fini;
+
+ /* check for known (emulated) devices */
+ if (pci->subsystem_vendor == 0x1af4 &&
+ pci->subsystem_device == 0x1100) {
+ /* KVM emulated sound, PCI SSID: 1af4:1100 */
+ msg = "enable KVM";
+ } else if (pci->subsystem_vendor == 0x1ab8) {
+ /* Parallels VM emulated sound, PCI SSID: 1ab8:xxxx */
+ msg = "enable Parallels VM";
+ } else {
+ msg = "disable (unknown or VT-d) VM";
+ result = 0;
+ }
+
+fini:
+ if (msg != NULL)
+ printk(KERN_INFO "intel8x0: %s optimization\n", msg);
return result;
}
@@ -3022,7 +3043,7 @@
if (xbox)
chip->xbox = 1;
- chip->inside_vm = snd_intel8x0_inside_vm();
+ chip->inside_vm = snd_intel8x0_inside_vm(pci);
if (pci->vendor == PCI_VENDOR_ID_INTEL &&
pci->device == PCI_DEVICE_ID_INTEL_440MX)