Patch "KVM: PPC: Book3S HV: Fix pending_pri value in kvmppc_xive_get_icp()" has been added to the 4.14-stable tree

[<gregkh@linuxfoundation.org>]

This is a note to let you know that I've just added the patch titled

    KVM: PPC: Book3S HV: Fix pending_pri value in kvmppc_xive_get_icp()

to the 4.14-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     kvm-ppc-book3s-hv-fix-pending_pri-value-in-kvmppc_xive_get_icp.patch
and it can be found in the queue-4.14 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From 7333b5aca412d6ad02667b5a513485838a91b136 Mon Sep 17 00:00:00 2001
From: Laurent Vivier <lvivier@redhat.com>
Date: Tue, 12 Dec 2017 18:23:56 +0100
Subject: KVM: PPC: Book3S HV: Fix pending_pri value in kvmppc_xive_get_icp()

From: Laurent Vivier <lvivier@redhat.com>

commit 7333b5aca412d6ad02667b5a513485838a91b136 upstream.

When we migrate a VM from a POWER8 host (XICS) to a POWER9 host
(XICS-on-XIVE), we have an error:

qemu-kvm: Unable to restore KVM interrupt controller state \
          (0xff000000) for CPU 0: Invalid argument

This is because kvmppc_xics_set_icp() checks the new state
is internaly consistent, and especially:

...
   1129         if (xisr == 0) {
   1130                 if (pending_pri != 0xff)
   1131                         return -EINVAL;
...

On the other side, kvmppc_xive_get_icp() doesn't set
neither the pending_pri value, nor the xisr value (set to 0)
(and kvmppc_xive_set_icp() ignores the pending_pri value)

As xisr is 0, pending_pri must be set to 0xff.

Fixes: 5af50993850a ("KVM: PPC: Book3S HV: Native usage of the XIVE interrupt controller")
Signed-off-by: Laurent Vivier <lvivier@redhat.com>
Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 arch/powerpc/kvm/book3s_xive.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

--- a/arch/powerpc/kvm/book3s_xive.c
+++ b/arch/powerpc/kvm/book3s_xive.c
@@ -725,7 +725,8 @@ u64 kvmppc_xive_get_icp(struct kvm_vcpu
 
 	/* Return the per-cpu state for state saving/migration */
 	return (u64)xc->cppr << KVM_REG_PPC_ICP_CPPR_SHIFT |
-	       (u64)xc->mfrr << KVM_REG_PPC_ICP_MFRR_SHIFT;
+	       (u64)xc->mfrr << KVM_REG_PPC_ICP_MFRR_SHIFT |
+	       (u64)0xff << KVM_REG_PPC_ICP_PPRI_SHIFT;
 }
 
 int kvmppc_xive_set_icp(struct kvm_vcpu *vcpu, u64 icpval)


Patches currently in stable-queue which might be from lvivier@redhat.com are

queue-4.14/kvm-ppc-book3s-hv-fix-pending_pri-value-in-kvmppc_xive_get_icp.patch
queue-4.14/kvm-ppc-book3s-fix-xive-migration-of-pending-interrupts.patch