KVM currently validates the size of the VPA registered by the client
against sizeof(struct lppaca), however we align (and therefore size)
that struct to 1kB to avoid crossing a 4kB boundary in the client.
PAPR calls for sizes >= 640 bytes to be accepted. Hard code this with
a comment.
Signed-off-by: Nicholas Piggin <npiggin@xxxxxxxxx>
---
arch/powerpc/kvm/book3s_hv.c | 8 +++++++-
1 file changed, 7 insertions(+), 1 deletion(-)
diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c
index 359c79cdf0cc..1182cfd79857 100644
--- a/arch/powerpc/kvm/book3s_hv.c
+++ b/arch/powerpc/kvm/book3s_hv.c
@@ -485,7 +485,13 @@ static unsigned long do_h_register_vpa(struct kvm_vcpu *vcpu,
switch (subfunc) {
case H_VPA_REG_VPA: /* register VPA */
- if (len < sizeof(struct lppaca))
+ /*
+ * The size of our lppaca is 1kB because of the way we align
+ * it for the guest to avoid crossing a 4kB boundary. We only
+ * use 640 bytes of the structure though, so we should accept
+ * clients that set a size of 640.
+ */
+ if (len < 640)
break;
vpap = &tvcpu->arch.vpa;
err = 0;
--
2.13.3
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