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| author | James Hogan <james.hogan@imgtec.com> | 2016-11-29 01:45:04 +0300 |
|---|---|---|
| committer | James Hogan <james.hogan@imgtec.com> | 2017-02-03 18:21:08 +0300 |
| commit | 4841e0dd4f53c127b11947bdbe4423b5e9014ebc (patch) | |
| tree | 20404edba5267e5071f79ec98815430c6cd666a5 /arch/mips/kvm/mips.c | |
| parent | 06c158c96ed8909a1d8696d4f953ca8a9ef55574 (diff) | |
| download | linux-4841e0dd4f53c127b11947bdbe4423b5e9014ebc.tar.xz | |
KVM: MIPS: Update vcpu->mode and vcpu->cpu
Keep the vcpu->mode and vcpu->cpu variables up to date so that
kvm_make_all_cpus_request() has a chance of functioning correctly. This
will soon need to be used for kvm_flush_remote_tlbs().
We can easily update vcpu->cpu when the VCPU context is loaded or saved,
which will happen when accessing guest context and when the guest is
scheduled in and out.
We need to be a little careful with vcpu->mode though, as we will in
future be checking for outstanding VCPU requests, and this must be done
after the value of IN_GUEST_MODE in vcpu->mode is visible to other CPUs.
Otherwise the other CPU could fail to trigger an IPI to wait for
completion dispite the VCPU request not being seen.
Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: "Radim Krčmář" <rkrcmar@redhat.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org
Diffstat (limited to 'arch/mips/kvm/mips.c')
| -rw-r--r-- | arch/mips/kvm/mips.c | 18 |
1 files changed, 18 insertions, 0 deletions
diff --git a/arch/mips/kvm/mips.c b/arch/mips/kvm/mips.c index 9b72e2c55a0c..ff5e34293227 100644 --- a/arch/mips/kvm/mips.c +++ b/arch/mips/kvm/mips.c @@ -365,6 +365,14 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu, struct kvm_run *run) guest_enter_irqoff(); trace_kvm_enter(vcpu); + /* + * Make sure the read of VCPU requests in vcpu_run() callback is not + * reordered ahead of the write to vcpu->mode, or we could miss a TLB + * flush request while the requester sees the VCPU as outside of guest + * mode and not needing an IPI. + */ + smp_store_mb(vcpu->mode, IN_GUEST_MODE); + r = kvm_mips_callbacks->vcpu_run(run, vcpu); trace_kvm_out(vcpu); @@ -1326,6 +1334,8 @@ int kvm_mips_handle_exit(struct kvm_run *run, struct kvm_vcpu *vcpu) u32 inst; int ret = RESUME_GUEST; + vcpu->mode = OUTSIDE_GUEST_MODE; + /* re-enable HTW before enabling interrupts */ htw_start(); @@ -1481,6 +1491,14 @@ skip_emul: if (ret == RESUME_GUEST) { trace_kvm_reenter(vcpu); + /* + * Make sure the read of VCPU requests in vcpu_reenter() + * callback is not reordered ahead of the write to vcpu->mode, + * or we could miss a TLB flush request while the requester sees + * the VCPU as outside of guest mode and not needing an IPI. + */ + smp_store_mb(vcpu->mode, IN_GUEST_MODE); + kvm_mips_callbacks->vcpu_reenter(run, vcpu); /* |