On Mon, May 21, 2018 at 12:09:41PM +0800, wei.guo.simon@xxxxxxxxx wrote: > From: Simon Guo <wei.guo.simon@xxxxxxxxx> > > Currently guest kernel doesn't handle TAR fac unavailable and it always > runs with TAR bit on. PR KVM will lazily enable TAR. TAR is not a > frequent-use reg and it is not included in SVCPU struct. > > Due to the above, the checkpointed TAR val might be a bogus TAR val. > To solve this issue, we will make vcpu->arch.fscr tar bit consistent > with shadow_fscr when TM enabled. > > At the end of emulating treclaim., the correct TAR val need to be loaded > into reg if FSCR_TAR bit is on. > At the beginning of emulating trechkpt., TAR needs to be flushed so that > the right tar val can be copy into tar_tm. > > Tested with: > tools/testing/selftests/powerpc/tm/tm-tar > tools/testing/selftests/powerpc/ptrace/ptrace-tm-tar (remove DSCR/PPR > related testing). With this patch, a 32-bit powermac compile with PR KVM enabled gives this error: arch/powerpc/kvm/book3s_pr.c:58:12: error: ‘kvmppc_handle_fac’ declared ‘static’ but never defined [-Werror=unused-function] static int kvmppc_handle_fac(struct kvm_vcpu *vcpu, ulong fac); ^ cc1: all warnings being treated as errors scripts/Makefile.build:312: recipe for target 'arch/powerpc/kvm/book3s_pr.o' failed The easy fix is a #ifdef CONFIG_PPC_BOOK3S_64 around the forward static definition. Paul.