On 14/02/2019 13:10, Paul Durrant wrote: > The current code uses hvm_asid_flush_vcpu() but this is insufficient for > a guest running in shadow mode, which results in guest crashes early in > boot if the 'hcall_remote_tlb_flush' is enabled. > > This patch, instead of open coding a new flush algorithm, adapts the one > already used by the HVMOP_flush_tlbs Xen hypercall. The implementation is > modified to allow TLB flushing a subset of a domain's vCPUs. A callback > function determines whether or not a vCPU requires flushing. This mechanism > was chosen because, while it is the case that the currently implemented > viridian hypercalls specify a vCPU mask, there are newer variants which > specify a sparse HV_VP_SET and thus use of a callback will avoid needing to > expose details of this outside of the viridian subsystem if and when those > newer variants are implemented. > > NOTE: Use of the common flush function requires that the hypercalls are > restartable and so, with this patch applied, viridian_hypercall() > can now return HVM_HCALL_preempted. This is safe as no modification > to struct cpu_user_regs is done before the return. > > Signed-off-by: Paul Durrant <paul.durr...@citrix.com> > --- > Cc: Jan Beulich <jbeul...@suse.com> > Cc: Andrew Cooper <andrew.coop...@citrix.com> > Cc: Wei Liu <wei.l...@citrix.com> > Cc: "Roger Pau Monné" <roger....@citrix.com> > > v2: > - Use cpumask_scratch
That's not a good idea. cpumask_scratch may be used from other cpus as long as the respectice scheduler lock is being held. See the comment in include/xen/sched-if.h: /* * Scratch space, for avoiding having too many cpumask_t on the stack. * Within each scheduler, when using the scratch mask of one pCPU: * - the pCPU must belong to the scheduler, * - the caller must own the per-pCPU scheduler lock (a.k.a. runqueue * lock). */ So please don't use cpumask_scratch outside the scheduler! Juergen _______________________________________________ Xen-devel mailing list Xen-devel@lists.xenproject.org https://lists.xenproject.org/mailman/listinfo/xen-devel
