From a36593e16757e524c1596d93914155bd8acbb90a Mon Sep 17 00:00:00 2001 From: Alexey Kardashevskiy Date: Thu, 11 Jan 2018 15:08:32 +1100 Subject: [PATCH] target/ppc: Yet another fix for KVM-HV HPTE accessors As stated in the 1ad9f0a464fe commit log, the returned entries are not a whole PTEG. It was not a problem before 1ad9f0a464fe as it would read a single record assuming it contains a whole PTEG but now the code tries reading the entire PTEG and "if ((n - i) < invalid)" produces negative values which then are converted to size_t for memset() and that throws seg fault. This fixes the math. While here, fix the last @i increment as well. Fixes: 1ad9f0a464fe "target/ppc: Fix KVM-HV HPTE accessors" Signed-off-by: Alexey Kardashevskiy Signed-off-by: David Gibson --- target/ppc/kvm.c | 11 +++++++---- 1 file changed, 7 insertions(+), 4 deletions(-) diff --git a/target/ppc/kvm.c b/target/ppc/kvm.c index 4664a3ce9d..09fcb082d2 100644 --- a/target/ppc/kvm.c +++ b/target/ppc/kvm.c @@ -2667,21 +2667,24 @@ void kvmppc_read_hptes(ppc_hash_pte64_t *hptes, hwaddr ptex, int n) hdr = (struct kvm_get_htab_header *)buf; while ((i < n) && ((char *)hdr < (buf + rc))) { - int invalid = hdr->n_invalid; + int invalid = hdr->n_invalid, valid = hdr->n_valid; if (hdr->index != (ptex + i)) { hw_error("kvmppc_read_hptes: Unexpected HPTE index %"PRIu32 " != (%"HWADDR_PRIu" + %d", hdr->index, ptex, i); } - memcpy(hptes + i, hdr + 1, HASH_PTE_SIZE_64 * hdr->n_valid); - i += hdr->n_valid; + if (n - i < valid) { + valid = n - i; + } + memcpy(hptes + i, hdr + 1, HASH_PTE_SIZE_64 * valid); + i += valid; if ((n - i) < invalid) { invalid = n - i; } memset(hptes + i, 0, invalid * HASH_PTE_SIZE_64); - i += hdr->n_invalid; + i += invalid; hdr = (struct kvm_get_htab_header *) ((char *)(hdr + 1) + HASH_PTE_SIZE_64 * hdr->n_valid); -- GitLab