[Qemu-devel] [PATCH 1/1] ppc: Fix MMU model values needed by PR KVM

[Sam Bobroff]

Commit 4322e8c "ppc: Fix 64K pages support in full emulation" added
the POWERPC_MMU_64K flag to the POWERPC_MMU_2_06 and POWERPC_MMU_2_07
definitions but not to their "degraded" variants. When running with PR
KVM, kvm_fixup_page_sizes() removes the POWERPC_MMU_1TSEG flag from
the MMU value then later ppc_tlb_invalidate_all() expects the value to
be one from the list, but it isn't because the POWERPC_MMU_64K bit is
missing from the (otherwise) matching "degraded" entry. This causes
QEMU to exit with "fatal: Unknown MMU model".

This patch adds the POWERPC_MMU_64K flag to the POWERPC_MMU_2_06a and
POWERPC_MMU_2_07a values, preventing the error.

Signed-off-by: Sam Bobroff <address@hidden>
---
I recently discovered that I can't start QEMU with KVM PR for modern
pseries machines:

$ rmmod kvm_hv
$ modprobe kvm-pr
$ qemu-system-ppc64 -nographic -vga none -machine pseries,accel=kvm
qemu: fatal: Unknown MMU model

A quick investigation seems to indicate that it's just a missing flag
in the MMU definition. If it's really that simple then here's a patch
for it.

Cheers,
Sam.

 target-ppc/cpu-qom.h | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/target-ppc/cpu-qom.h b/target-ppc/cpu-qom.h
index 2864105..0f1e011 100644
--- a/target-ppc/cpu-qom.h
+++ b/target-ppc/cpu-qom.h
@@ -71,6 +71,10 @@ enum powerpc_mmu_t {
 #define POWERPC_MMU_1TSEG    0x00020000
 #define POWERPC_MMU_AMR      0x00040000
 #define POWERPC_MMU_64K      0x00080000
+/* Any entry that include POWERPC_MMU_1TSEG must have a matching
+ * entry without it, because it may be removed by
+ * kvm_fixup_page_sizes() and the new value must exist here.
+ * See ppc_tlb_invalidate_*(). */
     /* 64 bits PowerPC MMU                                     */
     POWERPC_MMU_64B        = POWERPC_MMU_64 | 0x00000001,
     /* Architecture 2.03 and later (has LPCR) */
@@ -81,6 +85,7 @@ enum powerpc_mmu_t {
                              | POWERPC_MMU_AMR | 0x00000003,
     /* Architecture 2.06 "degraded" (no 1T segments)           */
     POWERPC_MMU_2_06a      = POWERPC_MMU_64 | POWERPC_MMU_AMR
+                             | POWERPC_MMU_64K
                              | 0x00000003,
     /* Architecture 2.07 variant                               */
     POWERPC_MMU_2_07       = POWERPC_MMU_64 | POWERPC_MMU_1TSEG
@@ -88,6 +93,7 @@ enum powerpc_mmu_t {
                              | POWERPC_MMU_AMR | 0x00000004,
     /* Architecture 2.07 "degraded" (no 1T segments)           */
     POWERPC_MMU_2_07a      = POWERPC_MMU_64 | POWERPC_MMU_AMR
+                             | POWERPC_MMU_64K
                              | 0x00000004,
 };
 
-- 
2.1.0