POWER8 and POWER9 have 12-bit LPIDs. Change LPID_RSVD to support up to
(4096 - 2) guests on these processors. POWER7 is kept the same with a
limitation of (1024 - 2), but it might be time to drop KVM support for
POWER7.
Tested with 2048 guests * 4 vCPUs on a witherspoon system with 512G
RAM and a bit of swap.
Signed-off-by: Cédric Le Goater <c...@kaod.org>
---
arch/powerpc/include/asm/reg.h | 3 ++-
arch/powerpc/kvm/book3s_64_mmu_hv.c | 8 ++++++--
2 files changed, 8 insertions(+), 3 deletions(-)
diff --git a/arch/powerpc/include/asm/reg.h b/arch/powerpc/include/asm/reg.h
index 88e6c78100d9..b70bbfb0ea3c 100644
--- a/arch/powerpc/include/asm/reg.h
+++ b/arch/powerpc/include/asm/reg.h
@@ -473,7 +473,8 @@
#ifndef SPRN_LPID
#define SPRN_LPID 0x13F /* Logical Partition Identifier */
#endif
-#define LPID_RSVD 0x3ff /* Reserved LPID for partn switching */
+#define LPID_RSVD_POWER7 0x3ff /* Reserved LPID for partn switching */
+#define LPID_RSVD 0xfff /* Reserved LPID for partn switching */
#define SPRN_HMER 0x150 /* Hypervisor maintenance exception reg
*/
#define HMER_DEBUG_TRIG (1ul << (63 - 17)) /* Debug trigger */
#define SPRN_HMEER 0x151 /* Hyp maintenance exception enable reg
*/
diff --git a/arch/powerpc/kvm/book3s_64_mmu_hv.c
b/arch/powerpc/kvm/book3s_64_mmu_hv.c
index 18aed9775a3c..23035ab2ec50 100644
--- a/arch/powerpc/kvm/book3s_64_mmu_hv.c
+++ b/arch/powerpc/kvm/book3s_64_mmu_hv.c
@@ -260,11 +260,15 @@ int kvmppc_mmu_hv_init(void)
if (!mmu_has_feature(MMU_FTR_LOCKLESS_TLBIE))
return -EINVAL;
- /* POWER7 has 10-bit LPIDs (12-bit in POWER8) */
host_lpid = 0;
if (cpu_has_feature(CPU_FTR_HVMODE))
host_lpid = mfspr(SPRN_LPID);
- rsvd_lpid = LPID_RSVD;
+
+ /* POWER8 and above have 12-bit LPIDs (10-bit in POWER7) */
+ if (cpu_has_feature(CPU_FTR_ARCH_207S))
+ rsvd_lpid = LPID_RSVD;
+ else
+ rsvd_lpid = LPID_RSVD_POWER7;
kvmppc_init_lpid(rsvd_lpid + 1);
--
2.25.4
