> -----Original Message----- > From: kvm-ppc-owner@xxxxxxxxxxxxxxx > [mailto:kvm-ppc-owner@xxxxxxxxxxxxxxx] On Behalf Of Alexander Graf > Sent: Thursday, March 31, 2011 3:51 PM > To: Liu Yu-B13201 > Cc: Wood Scott-B07421; kvm-ppc@xxxxxxxxxxxxxxx > Subject: Re: [PATCH v5 4/4] KVM: PPC: e500: Save/restore SPE state > > > On 31.03.2011, at 05:21, Liu Yu-B13201 wrote: > > > > > > >> -----Original Message----- > >> From: kvm-ppc-owner@xxxxxxxxxxxxxxx > >> [mailto:kvm-ppc-owner@xxxxxxxxxxxxxxx] On Behalf Of Scott Wood > >> Sent: Thursday, March 31, 2011 7:35 AM > >> To: agraf@xxxxxxx > >> Cc: kvm-ppc@xxxxxxxxxxxxxxx > >> Subject: [PATCH v5 4/4] KVM: PPC: e500: Save/restore SPE state > >> > >> This is done lazily. The SPE save will be done only if > the guest has > >> used SPE since the last preemption or heavyweight exit. > >> Restore will be > >> done only on demand, when enabling MSR_SPE in the shadow MSR, > >> in response > >> to an SPE fault or mtmsr emulation. > >> > >> For SPEFSCR, Linux already switches it on context switch > >> (non-lazily), so > >> the only remaining bit is to save it between qemu and the guest. > >> > >> Signed-off-by: Liu Yu <yu.liu@xxxxxxxxxxxxx> > >> Signed-off-by: Scott Wood <scottwood@xxxxxxxxxxxxx> > >> --- > >> v5: disable preemption when restoring SPE state > >> > >> Saving SPE state is only done from a preempt notifier or > vcpu_put(), > >> where preemption is already disabled. > >> > >> The other patches in this series are the same as v4. > >> > >> arch/powerpc/include/asm/kvm_host.h | 6 +++ > >> arch/powerpc/include/asm/reg_booke.h | 1 + > >> arch/powerpc/kernel/asm-offsets.c | 6 +++ > >> arch/powerpc/kvm/booke.c | 72 > >> +++++++++++++++++++++++++++++++++- > >> arch/powerpc/kvm/booke.h | 18 ++------- > >> arch/powerpc/kvm/booke_interrupts.S | 40 +++++++++++++++++++ > >> arch/powerpc/kvm/e500.c | 19 ++++++++- > >> 7 files changed, 145 insertions(+), 17 deletions(-) > >> > > > > I think the patch miss the bit to handle the case that > > if guest clear the MSR_SPE. > > Right. On set_msr the shadow_msr should get MSR_SPE removed. > Thanks for the catch! > BTW, looks like guest trap on MSR[SPE] in para virt mode for now, is it? If we don't want to trap on that, then shadow_msr doesn't work here. That's the intend to use msr_block.. Thanks, Yu -- To unsubscribe from this list: send the line "unsubscribe kvm-ppc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
