>>> On 26.05.16 at 15:39, <feng...@intel.com> wrote: > Normally, in vmx_cpu_block() 'NDST' filed should have the same > value with 'dest' or 'MASK_INSR(dest, PI_xAPIC_NDST_MASK)' depending > on whether x2apic is enabled. However, in the following scenario, > 'NDST' has different value: > > 'vcpu_block' hook gets assigned in vmx_pi_hooks_assign(), but all > other three PI hooks have not been assigned or not been excuted yet. > And during this interval, we are running in vmx_vcpu_block(), then > 'NDST' may have different value.
How about simply assigning vcpu_block last? Or alternatively holding pi_blocking_list_lock around all four assignments? Or (maybe in addition to one of these) writing something sensible in vmx_pi_hooks_assign() before doing the hook assignments? Of course much depends on whether the ASSERT() you replace was meant just as a sanity check, or instead logic elsewhere relies on NDST having the right value already before getting into vmx_vcpu_block(). Also, rather than saying twice that NDST has a different value in that case, how about stating what exact value it has then and why that's not what we want/need? (Same goes for the code comment then.) > This patch fix this concern case. Here as well as in earlier patches - do you perhaps mean "corner case"? Jan _______________________________________________ Xen-devel mailing list Xen-devel@lists.xen.org http://lists.xen.org/xen-devel
