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powerpc/papr_scm: Use the correct bind address

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When binding an SCM volume to a physical address the hypervisor has the
option to return early with a continue token with the expectation that
the guest will resume the bind operation until it completes. A quirk of
this interface is that the bind address will only be returned by the
first bind h-call and the subsequent calls will return
0xFFFF_FFFF_FFFF_FFFF for the bind address.

We currently do not save the address returned by the first h-call. As a
result we will use the junk address as the base of the bound region if
the hypervisor decides to split the bind across multiple h-calls. This
bug was found when testing with very large SCM volumes where the bind
process would take more time than they hypervisor's internal h-call time
limit would allow. This patch fixes the issue by saving the bind address
from the first call.

Cc: stable@vger.kernel.org
Fixes: b5beae5e22 ("powerpc/pseries: Add driver for PAPR SCM regions")
Signed-off-by: Oliver O'Halloran <oohall@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
This commit is contained in:
Oliver O'Halloran 2019-01-31 12:53:47 +11:00 committed by Michael Ellerman
parent 579b9239c1
commit 5a3840a470
1 changed files with 4 additions and 1 deletions
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5
arch/powerpc/platforms/pseries/papr_scm.c
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@ -43,6 +43,7 @@ static int drc_pmem_bind(struct papr_scm_priv *p)
{ {
unsigned long ret[PLPAR_HCALL_BUFSIZE]; unsigned long ret[PLPAR_HCALL_BUFSIZE];
uint64_t rc, token; uint64_t rc, token;
uint64_t saved = 0;
/* /*
* When the hypervisor cannot map all the requested memory in a single * When the hypervisor cannot map all the requested memory in a single
@ -56,6 +57,8 @@ static int drc_pmem_bind(struct papr_scm_priv *p)
rc = plpar_hcall(H_SCM_BIND_MEM, ret, p->drc_index, 0, rc = plpar_hcall(H_SCM_BIND_MEM, ret, p->drc_index, 0,
p->blocks, BIND_ANY_ADDR, token); p->blocks, BIND_ANY_ADDR, token);
token = ret[0]; token = ret[0];
if (!saved)
saved = ret[1];
cond_resched(); cond_resched();
} while (rc == H_BUSY); } while (rc == H_BUSY);
@ -64,7 +67,7 @@ static int drc_pmem_bind(struct papr_scm_priv *p)
return -ENXIO; return -ENXIO;
} }
p->bound_addr = ret[1]; p->bound_addr = saved;
dev_dbg(&p->pdev->dev, "bound drc %x to %pR\n", p->drc_index, &p->res); dev_dbg(&p->pdev->dev, "bound drc %x to %pR\n", p->drc_index, &p->res);