File 5dd8126b-x86-vLAPIC-allow-APIC_SPIV_FOCUS_DISAB... of Package xen

Overview Repositories Revisions Requests Users Attributes Meta

File 5dd8126b-x86-vLAPIC-allow-APIC_SPIV_FOCUS_DISABLED.patch of Package xen (Revision a90efdcc88577026ef2a13678bb8ab98)

Currently displaying revision a90efdcc88577026ef2a13678bb8ab98 , Show latest

# Commit d7cd999faa1edf745a7597db811956cb882a5436
# Date 2019-11-22 17:52:59 +0100
# Author Roger Pau Monné <roger.pau@citrix.com>
# Committer Jan Beulich <jbeulich@suse.com>
x86/vlapic: allow setting APIC_SPIV_FOCUS_DISABLED in x2APIC mode

Current code unconditionally prevents setting APIC_SPIV_FOCUS_DISABLED
regardless of the processor model, which is not correct according to
the specification.

This issue was discovered while trying to boot a pvshim with x2APIC
enabled.

Always allow setting APIC_SPIV_FOCUS_DISABLED: the local APIC
provided to guests is emulated by Xen, and as such doesn't depend on
the features found on the hardware processor. Note for example that
Xen offers x2APIC support to guests even when the underlying hardware
doesn't have such feature.

Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>

--- a/xen/arch/x86/hvm/vlapic.c
+++ b/xen/arch/x86/hvm/vlapic.c
@@ -982,6 +982,7 @@ int guest_wrmsr_x2apic(struct vcpu *v, u
 
     case APIC_SPIV:
         if ( msr_content & ~(APIC_VECTOR_MASK | APIC_SPIV_APIC_ENABLED |
+                             APIC_SPIV_FOCUS_DISABLED |
                              (VLAPIC_VERSION & APIC_LVR_DIRECTED_EOI
                               ? APIC_SPIV_DIRECTED_EOI : 0)) )
             return X86EMUL_EXCEPTION;

Places

File 5dd8126b-x86-vLAPIC-allow-APIC_SPIV_FOCUS_DISABLED.patch of Package xen (Revision a90efdcc88577026ef2a13678bb8ab98)

Places