From b5aec39672dc6084b43fa3f77764a6f549255a53 Mon Sep 17 00:00:00 2001 From: David Gibson Date: Mon, 27 Feb 2012 17:18:07 +0000 Subject: pseries: Don't try to munmap() a malloc()ed TCE table For the pseries machine, TCE (IOMMU) tables can either be directly malloc()ed in qemu or, when running on a KVM which supports it, mmap()ed from a KVM ioctl. The latter option is used when available, because it allows the (frequent bottlenext) H_PUT_TCE hypercall to be KVM accelerated. However, even when KVM is persent, TCE acceleration is not always possible. Only KVM HV supports this ioctl(), not KVM PR, or the kernel could run out of contiguous memory to allocate the new table. In this case we need to fall back on the malloc()ed table. When a device is removed, and we need to remove the TCE table, we need to either munmap() or free() the table as appropriate for how it was allocated. The code is supposed to do that, but we buggily fail to initialize the tcet->fd variable in the malloc() case, which is used as a flag to determine which is the right choice. This patch fixes the bug, and cleans up error messages relating to this path while we're at it. Signed-off-by: Benjamin Herrenschmidt Signed-off-by: David Gibson Signed-off-by: Alexander Graf --- target-ppc/kvm.c | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-) diff --git a/target-ppc/kvm.c b/target-ppc/kvm.c index aeb3de9ae..724f4c781 100644 --- a/target-ppc/kvm.c +++ b/target-ppc/kvm.c @@ -843,12 +843,18 @@ void *kvmppc_create_spapr_tce(uint32_t liobn, uint32_t window_size, int *pfd) int fd; void *table; + /* Must set fd to -1 so we don't try to munmap when called for + * destroying the table, which the upper layers -will- do + */ + *pfd = -1; if (!cap_spapr_tce) { return NULL; } fd = kvm_vm_ioctl(kvm_state, KVM_CREATE_SPAPR_TCE, &args); if (fd < 0) { + fprintf(stderr, "KVM: Failed to create TCE table for liobn 0x%x\n", + liobn); return NULL; } @@ -857,6 +863,8 @@ void *kvmppc_create_spapr_tce(uint32_t liobn, uint32_t window_size, int *pfd) table = mmap(NULL, len, PROT_READ|PROT_WRITE, MAP_SHARED, fd, 0); if (table == MAP_FAILED) { + fprintf(stderr, "KVM: Failed to map TCE table for liobn 0x%x\n", + liobn); close(fd); return NULL; } @@ -876,8 +884,8 @@ int kvmppc_remove_spapr_tce(void *table, int fd, uint32_t window_size) len = (window_size / SPAPR_VIO_TCE_PAGE_SIZE)*sizeof(VIOsPAPR_RTCE); if ((munmap(table, len) < 0) || (close(fd) < 0)) { - fprintf(stderr, "KVM: Unexpected error removing KVM SPAPR TCE " - "table: %s", strerror(errno)); + fprintf(stderr, "KVM: Unexpected error removing TCE table: %s", + strerror(errno)); /* Leak the table */ } -- cgit v1.2.3