From 74b41e5676568e6560474267bbf1a5a32d3e2c41 Mon Sep 17 00:00:00 2001 From: David Gibson Date: Thu, 27 Oct 2011 15:56:31 +0000 Subject: [PATCH] pseries: Allow writes to KVM accelerated TCE table Sufficiently recent kernels include a KVM call to accelerate use of PAPR TCE tables (IOMMU), which are used by PAPR virtual IO devices. This involves qemu mapping the TCE table in from a kernel obtained fd, which currently we do with PROT_READ only. This is a hangover from early (never released) versions of this kernel interface which only permitted read-only mappings and required us to destroy and recreate the table when we needed to clear it from qemu. Now, the kernel permits read-write mappings, and we rely on this to clear the table in spapr_vio_quiesce_one(). However, due to insufficient testing, I forgot to update the actual mapping of the table in kvmppc_create_spapr_tce() to add PROT_WRITE to the mmap(). This patch corrects the oversight. Signed-off-by: David Gibson Signed-off-by: Alexander Graf --- target-ppc/kvm.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/target-ppc/kvm.c b/target-ppc/kvm.c index f3d0861a1..429349fb9 100644 --- a/target-ppc/kvm.c +++ b/target-ppc/kvm.c @@ -850,7 +850,7 @@ void *kvmppc_create_spapr_tce(uint32_t liobn, uint32_t window_size, int *pfd) len = (window_size / SPAPR_VIO_TCE_PAGE_SIZE) * sizeof(VIOsPAPR_RTCE); /* FIXME: round this up to page size */ - table = mmap(NULL, len, PROT_READ, MAP_SHARED, fd, 0); + table = mmap(NULL, len, PROT_READ|PROT_WRITE, MAP_SHARED, fd, 0); if (table == MAP_FAILED) { close(fd); return NULL; -- 2.39.5