From faa6d21153fd11e139dd880044521389b34a24f2 Mon Sep 17 00:00:00 2001 From: "Aneesh Kumar K.V" Date: Tue, 3 Sep 2019 18:04:52 +0530 Subject: [PATCH] powerpc/nvdimm: use H_SCM_QUERY hcall on H_OVERLAP error Right now we force an unbind of SCM memory at drcindex on H_OVERLAP error. This really slows down operations like kexec where we get the H_OVERLAP error because we don't go through a full hypervisor re init. H_OVERLAP error for a H_SCM_BIND_MEM hcall indicates that SCM memory at drc index is already bound. Since we don't specify a logical memory address for bind hcall, we can use the H_SCM_QUERY hcall to query the already bound logical address. Boot time difference with and without patch is: [ 5.583617] IOMMU table initialized, virtual merging enabled [ 5.603041] papr_scm ibm,persistent-memory:ibm,pmemory@44104001: Retrying bind after unbinding [ 301.514221] papr_scm ibm,persistent-memory:ibm,pmemory@44108001: Retrying bind after unbinding [ 340.057238] hv-24x7: read 1530 catalog entries, created 537 event attrs (0 failures), 275 descs after fix [ 5.101572] IOMMU table initialized, virtual merging enabled [ 5.116984] papr_scm ibm,persistent-memory:ibm,pmemory@44104001: Querying SCM details [ 5.117223] papr_scm ibm,persistent-memory:ibm,pmemory@44108001: Querying SCM details [ 5.120530] hv-24x7: read 1530 catalog entries, created 537 event attrs (0 failures), 275 descs Signed-off-by: Aneesh Kumar K.V Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20190903123452.28620-2-aneesh.kumar@linux.ibm.com --- arch/powerpc/platforms/pseries/papr_scm.c | 48 +++++++++++++++++++++++++------ 1 file changed, 40 insertions(+), 8 deletions(-) diff --git a/arch/powerpc/platforms/pseries/papr_scm.c b/arch/powerpc/platforms/pseries/papr_scm.c index 3bef4d2..6188329 100644 --- a/arch/powerpc/platforms/pseries/papr_scm.c +++ b/arch/powerpc/platforms/pseries/papr_scm.c @@ -65,10 +65,8 @@ static int drc_pmem_bind(struct papr_scm_priv *p) cond_resched(); } while (rc == H_BUSY); - if (rc) { - dev_err(&p->pdev->dev, "bind err: %lld\n", rc); + if (rc) return rc; - } p->bound_addr = saved; dev_dbg(&p->pdev->dev, "bound drc 0x%x to %pR\n", p->drc_index, &p->res); @@ -110,6 +108,42 @@ static void drc_pmem_unbind(struct papr_scm_priv *p) return; } +static int drc_pmem_query_n_bind(struct papr_scm_priv *p) +{ + unsigned long start_addr; + unsigned long end_addr; + unsigned long ret[PLPAR_HCALL_BUFSIZE]; + int64_t rc; + + + rc = plpar_hcall(H_SCM_QUERY_BLOCK_MEM_BINDING, ret, + p->drc_index, 0); + if (rc) + goto err_out; + start_addr = ret[0]; + + /* Make sure the full region is bound. */ + rc = plpar_hcall(H_SCM_QUERY_BLOCK_MEM_BINDING, ret, + p->drc_index, p->blocks - 1); + if (rc) + goto err_out; + end_addr = ret[0]; + + if ((end_addr - start_addr) != ((p->blocks - 1) * p->block_size)) + goto err_out; + + p->bound_addr = start_addr; + dev_dbg(&p->pdev->dev, "bound drc 0x%x to %pR\n", p->drc_index, &p->res); + return rc; + +err_out: + dev_info(&p->pdev->dev, + "Failed to query, trying an unbind followed by bind"); + drc_pmem_unbind(p); + return drc_pmem_bind(p); +} + + static int papr_scm_meta_get(struct papr_scm_priv *p, struct nd_cmd_get_config_data_hdr *hdr) { @@ -430,13 +464,11 @@ static int papr_scm_probe(struct platform_device *pdev) rc = drc_pmem_bind(p); /* If phyp says drc memory still bound then force unbound and retry */ - if (rc == H_OVERLAP) { - dev_warn(&pdev->dev, "Retrying bind after unbinding\n"); - drc_pmem_unbind(p); - rc = drc_pmem_bind(p); - } + if (rc == H_OVERLAP) + rc = drc_pmem_query_n_bind(p); if (rc != H_SUCCESS) { + dev_err(&p->pdev->dev, "bind err: %d\n", rc); rc = -ENXIO; goto err; } -- 2.7.4