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From: David Gibson <david@gibson.dropbear.id.au>
To: benh@kernel.crashing.org, aik@ozlabs.ru, agraf@suse.de
Cc: qemu-ppc@nongnu.org, qemu-devel@nongnu.org,
	David Gibson <david@gibson.dropbear.id.au>
Subject: [Qemu-devel] [PATCHv2 6/7] target-ppc: Remove hack for ppc_hash64_load_hpte*() with HV KVM
Date: Tue,  9 Feb 2016 12:12:25 +1000	[thread overview]
Message-ID: <1454983946-32073-7-git-send-email-david@gibson.dropbear.id.au> (raw)
In-Reply-To: <1454983946-32073-1-git-send-email-david@gibson.dropbear.id.au>

With HV KVM, the guest's hash page table (HPT) is managed by the kernel and
not directly accessible to QEMU.  This means that spapr->htab is NULL
and normally env->external_htab would also be NULL for each cpu.

However, that would cause ppc_hash64_load_hpte*() to do the wrong thing in
the few cases where QEMU does need to load entries from the in-kernel HPT.
Specifically, seeing external_htab is NULL, they would look for an HPT
within the guest's address space instead.

To stop that we have an ugly hack in the pseries machine type code to
set external htab to (void *)1 instead.

This patch removes that hack by having ppc_hash64_load_hpte*() explicitly
check kvmppc_kern_htab instead, which makes more sense.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Reviewed-by: Alexey Kardashevskiy <aik@ozlabs.ru>
---
 hw/ppc/spapr.c          | 7 -------
 target-ppc/mmu-hash64.h | 4 ++--
 2 files changed, 2 insertions(+), 9 deletions(-)

diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
index 907439a..c85a125 100644
--- a/hw/ppc/spapr.c
+++ b/hw/ppc/spapr.c
@@ -1197,13 +1197,6 @@ static void spapr_cpu_reset(void *opaque)
     env->spr[SPR_HIOR] = 0;
 
     env->external_htab = (uint8_t *)spapr->htab;
-    if (kvm_enabled() && !env->external_htab) {
-        /*
-         * HV KVM, set external_htab to 1 so our ppc_hash64_load_hpte*
-         * functions do the right thing.
-         */
-        env->external_htab = (void *)1;
-    }
     env->htab_base = -1;
     /*
      * htab_mask is the mask used to normalize hash value to PTEG index.
diff --git a/target-ppc/mmu-hash64.h b/target-ppc/mmu-hash64.h
index ab0f86b..e7d9925 100644
--- a/target-ppc/mmu-hash64.h
+++ b/target-ppc/mmu-hash64.h
@@ -102,7 +102,7 @@ static inline target_ulong ppc_hash64_load_hpte0(PowerPCCPU *cpu,
     uint64_t addr;
 
     addr = token + (index * HASH_PTE_SIZE_64);
-    if (env->external_htab) {
+    if (kvmppc_kern_htab || env->external_htab) {
         return  ldq_p((const void *)(uintptr_t)addr);
     } else {
         return ldq_phys(CPU(cpu)->as, addr);
@@ -116,7 +116,7 @@ static inline target_ulong ppc_hash64_load_hpte1(PowerPCCPU *cpu,
     uint64_t addr;
 
     addr = token + (index * HASH_PTE_SIZE_64) + HASH_PTE_SIZE_64/2;
-    if (env->external_htab) {
+    if (kvmppc_kern_htab || env->external_htab) {
         return  ldq_p((const void *)(uintptr_t)addr);
     } else {
         return ldq_phys(CPU(cpu)->as, addr);
-- 
2.5.0

  parent reply	other threads:[~2016-02-09  2:11 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-02-09  2:12 [Qemu-devel] [PATCHv2 0/7] Cleanups to Hash Page Table handling David Gibson
2016-02-09  2:12 ` [Qemu-devel] [PATCHv2 1/7] target-ppc: Remove unused kvmppc_update_sdr1() stub David Gibson
2016-02-09  2:12 ` [Qemu-devel] [PATCHv2 2/7] target-ppc: Include missing MMU models for SDR1 in info registers David Gibson
2016-02-09  2:12 ` [Qemu-devel] [PATCHv2 3/7] pseries: Simplify handling of the hash page table fd David Gibson
2016-02-09  2:12 ` [Qemu-devel] [PATCHv2 4/7] pseries: Add helper to calculate recommended hash page table size David Gibson
2016-02-09  2:12 ` [Qemu-devel] [PATCHv2 5/7] pseries: Move hash page table allocation to reset time David Gibson
2016-02-09  2:59   ` Alexey Kardashevskiy
2016-02-09  2:12 ` David Gibson [this message]
2016-02-09  2:12 ` [Qemu-devel] [PATCHv2 7/7] target-ppc: Add helpers for updating a CPU's SDR1 and external HPT David Gibson
2016-02-11  0:51 ` [Qemu-devel] [PATCHv2 0/7] Cleanups to Hash Page Table handling David Gibson

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