Re: [PATCH RFC 0/4] KVM: MIPS: Provide arch-specific kvm_flush_remote_tlbs()

From: Peter Xu
Date: Wed Mar 11 2020 - 14:32:10 EST


On Wed, Feb 12, 2020 at 01:25:30PM +0100, Paolo Bonzini wrote:
> On 07/02/20 23:35, Peter Xu wrote:
> > [This series is RFC because I don't have MIPS to compile and test]
> >
> > kvm_flush_remote_tlbs() can be arch-specific, by either:
> >
> > - Completely replace kvm_flush_remote_tlbs(), like ARM, who is the
> > only user of CONFIG_HAVE_KVM_ARCH_TLB_FLUSH_ALL so far
> >
> > - Doing something extra before kvm_flush_remote_tlbs(), like MIPS VZ
> > support, however still wants to have the common tlb flush to be part
> > of the process. Could refer to kvm_vz_flush_shadow_all(). Then in
> > MIPS it's awkward to flush remote TLBs: we'll need to call the mips
> > hooks.
> >
> > It's awkward to have different ways to specialize this procedure,
> > especially MIPS cannot use the genenal interface which is quite a
> > pity. It's good to make it a common interface.
> >
> > This patch series removes the 2nd MIPS usage above, and let it also
> > use the common kvm_flush_remote_tlbs() interface. It should be
> > suggested that we always keep kvm_flush_remote_tlbs() be a common
> > entrance for tlb flushing on all archs.
> >
> > This idea comes from the reading of Sean's patchset on dynamic memslot
> > allocation, where a new dirty log specific hook is added for flushing
> > TLBs only for the MIPS code [1]. With this patchset, logically the
> > new hook in that patch can be dropped so we can directly use
> > kvm_flush_remote_tlbs().
> >
> > TODO: We can even extend another common interface for ranged TLB, but
> > let's see how we think about this series first.
> >
> > Any comment is welcomed, thanks.
> >
> > Peter Xu (4):
> > KVM: Provide kvm_flush_remote_tlbs_common()
> > KVM: MIPS: Drop flush_shadow_memslot() callback
> > KVM: MIPS: Replace all the kvm_flush_remote_tlbs() references
> > KVM: MIPS: Define arch-specific kvm_flush_remote_tlbs()
> >
> > arch/mips/include/asm/kvm_host.h | 7 -------
> > arch/mips/kvm/Kconfig | 1 +
> > arch/mips/kvm/mips.c | 22 ++++++++++------------
> > arch/mips/kvm/trap_emul.c | 15 +--------------
> > arch/mips/kvm/vz.c | 14 ++------------
> > include/linux/kvm_host.h | 1 +
> > virt/kvm/kvm_main.c | 10 ++++++++--
> > 7 files changed, 23 insertions(+), 47 deletions(-)
> >
>
> Compile-tested and queued.

Just in case it fells through the crach - Paolo, do you still have
plan to queue this again?

Thanks,

--
Peter Xu