| From ea02057cb7e92a508f452d110869a520e04764b1 Mon Sep 17 00:00:00 2001 |
| From: Sasha Levin <sashal@kernel.org> |
| Date: Thu, 24 Oct 2019 15:05:41 +0530 |
| Subject: powerpc/pseries: Don't fail hash page table insert for bolted mapping |
| |
| From: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> |
| |
| [ Upstream commit 75838a3290cd4ebbd1f567f310ba04b6ef017ce4 ] |
| |
| If the hypervisor returned H_PTEG_FULL for H_ENTER hcall, retry a hash page table |
| insert by removing a random entry from the group. |
| |
| After some runtime, it is very well possible to find all the 8 hash page table |
| entry slot in the hpte group used for mapping. Don't fail a bolted entry insert |
| in that case. With Storage class memory a user can find this error easily since |
| a namespace enable/disable is equivalent to memory add/remove. |
| |
| This results in failures as reported below: |
| |
| $ ndctl create-namespace -r region1 -t pmem -m devdax -a 65536 -s 100M |
| libndctl: ndctl_dax_enable: dax1.3: failed to enable |
| Error: namespace1.2: failed to enable |
| |
| failed to create namespace: No such device or address |
| |
| In kernel log we find the details as below: |
| |
| Unable to create mapping for hot added memory 0xc000042006000000..0xc00004200d000000: -1 |
| dax_pmem: probe of dax1.3 failed with error -14 |
| |
| This indicates that we failed to create a bolted hash table entry for direct-map |
| address backing the namespace. |
| |
| We also observe failures such that not all namespaces will be enabled with |
| ndctl enable-namespace all command. |
| |
| Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> |
| Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> |
| Link: https://lore.kernel.org/r/20191024093542.29777-2-aneesh.kumar@linux.ibm.com |
| Signed-off-by: Sasha Levin <sashal@kernel.org> |
| --- |
| arch/powerpc/mm/hash_utils_64.c | 9 ++++++++- |
| 1 file changed, 8 insertions(+), 1 deletion(-) |
| |
| diff --git a/arch/powerpc/mm/hash_utils_64.c b/arch/powerpc/mm/hash_utils_64.c |
| index b1007e9a31ba..11b41383e167 100644 |
| --- a/arch/powerpc/mm/hash_utils_64.c |
| +++ b/arch/powerpc/mm/hash_utils_64.c |
| @@ -296,7 +296,14 @@ int htab_bolt_mapping(unsigned long vstart, unsigned long vend, |
| ret = mmu_hash_ops.hpte_insert(hpteg, vpn, paddr, tprot, |
| HPTE_V_BOLTED, psize, psize, |
| ssize); |
| - |
| + if (ret == -1) { |
| + /* Try to remove a non bolted entry */ |
| + ret = mmu_hash_ops.hpte_remove(hpteg); |
| + if (ret != -1) |
| + ret = mmu_hash_ops.hpte_insert(hpteg, vpn, paddr, tprot, |
| + HPTE_V_BOLTED, psize, psize, |
| + ssize); |
| + } |
| if (ret < 0) |
| break; |
| |
| -- |
| 2.20.1 |
| |