File 0100-PPC-KVM-Make-pv-hcall-endian-agnost.patch of Package qemu

Overview Repositories Revisions Requests Users Attributes Meta

File 0100-PPC-KVM-Make-pv-hcall-endian-agnost.patch of Package qemu

From f2509ec403858c330eacc39777c22234ed25e986 Mon Sep 17 00:00:00 2001
From: Alexander Graf <agraf@suse.de>
Date: Wed, 11 Jun 2014 12:19:03 +0200
Subject: [PATCH] PPC: KVM: Make pv hcall endian agnostic

There were a few revisions of the Linux kernel that incorrectly swapped
the hcall instructions when they saw ePAPR compliant hypercalls.

We already have fixups for those in place when running with PR KVM, but
HV KVM and systems that don't implement hypercalls at all are still broken
because they fall back to the QEMU implementation of fallback hypercalls.

So let's make the fallback hypercall instruction path endian agnostic. This
only really works well for 64bit guests, but I don't think there are any 32bit
systems left that don't implement real pv hcall support, so we'll never get
into this code path.

Signed-off-by: Alexander Graf <agraf@suse.de>
(cherry picked from commit d13fc32ecf8d810ec9894a35e1cfae81f7d88039)
---
 target-ppc/kvm.c | 16 ++++++++--------
 1 file changed, 8 insertions(+), 8 deletions(-)

diff --git a/target-ppc/kvm.c b/target-ppc/kvm.c
index f7528bd332..167cc5a95a 100644
--- a/target-ppc/kvm.c
+++ b/target-ppc/kvm.c
@@ -1493,18 +1493,18 @@ int kvmppc_get_hypercall(CPUPPCState *env, uint8_t *buf, int buf_len)
     }
 
     /*
-     * Fallback to always fail hypercalls:
+     * Fallback to always fail hypercalls regardless of endianness:
      *
+     *     tdi 0,r0,72 (becomes b .+8 in wrong endian, nop in good endian)
      *     li r3, -1
-     *     nop
-     *     nop
-     *     nop
+     *     b .+8       (becomes nop in wrong endian)
+     *     bswap32(li r3, -1)
      */
 
-    hc[0] = 0x3860ffff;
-    hc[1] = 0x60000000;
-    hc[2] = 0x60000000;
-    hc[3] = 0x60000000;
+    hc[0] = cpu_to_be32(0x08000048);
+    hc[1] = cpu_to_be32(0x3860ffff);
+    hc[2] = cpu_to_be32(0x48000008);
+    hc[3] = cpu_to_be32(bswap32(0x3860ffff));
 
     return 0;
 }

Places

File 0100-PPC-KVM-Make-pv-hcall-endian-agnost.patch of Package qemu

Places