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KVM: PPC: Book3S HV: Invalidate TLB when nested vcpu moves physical cpu

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This is only done at level 0, since only level 0 knows which physical
CPU a vcpu is running on.  This does for nested guests what L0 already
did for its own guests, which is to flush the TLB on a pCPU when it
goes to run a vCPU there, and there is another vCPU in the same VM
which previously ran on this pCPU and has now started to run on another
pCPU.  This is to handle the situation where the other vCPU touched
a mapping, moved to another pCPU and did a tlbiel (local-only tlbie)
on that new pCPU and thus left behind a stale TLB entry on this pCPU.

This introduces a limit on the the vcpu_token values used in the
H_ENTER_NESTED hcall -- they must now be less than NR_CPUS.

[paulus@ozlabs.org - made prev_cpu array be short[] to reduce
 memory consumption.]

Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Suraj Jitindar Singh <sjitindarsingh@gmail.com>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
This commit is contained in:
Suraj Jitindar Singh
2018-10-08 16:31:11 +11:00
committed by Michael Ellerman
parent 690ed4cad8
commit 9d0b048da7
3 changed files with 71 additions and 38 deletions
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5
arch/powerpc/kvm/book3s_hv_nested.c
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@@ -168,6 +168,9 @@ long kvmhv_enter_nested_guest(struct kvm_vcpu *vcpu)
if (err)
return H_PARAMETER;
if (l2_hv.vcpu_token >= NR_CPUS)
return H_PARAMETER;
/* translate lpid */
l2 = kvmhv_get_nested(vcpu->kvm, l2_hv.lpid, true);
if (!l2)
@@ -412,6 +415,8 @@ struct kvm_nested_guest *kvmhv_alloc_nested(struct kvm *kvm, unsigned int lpid)
goto out_free2;
gp->shadow_lpid = shadow_lpid;
memset(gp->prev_cpu, -1, sizeof(gp->prev_cpu));
return gp;
out_free2: