This will prevent a hard to track down bug. It is related to
commit ffdb781883abd3215287ba1b1853f3d437d1240c
x86/hvm: prevent gcc uninitialised var warning
Which will preset "gmfn" to ~0UL.
This code will check if there is a path where bufioreq_pfn is passed
to hvm_free_ioreq_gmfn() and it is uninitialised, the BUG_ON will
report it.
Reported-by: Andrew Cooper <andrew.coop...@citrix.com>
Signed-off-by: Don Slutz <dsl...@verizon.com>
---
xen/arch/x86/hvm/hvm.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/xen/arch/x86/hvm/hvm.c b/xen/arch/x86/hvm/hvm.c
index ade99c0..0abac7c 100644
--- a/xen/arch/x86/hvm/hvm.c
+++ b/xen/arch/x86/hvm/hvm.c
@@ -536,8 +536,9 @@ static int hvm_alloc_ioreq_gmfn(struct domain *d, unsigned
long *gmfn)
static void hvm_free_ioreq_gmfn(struct domain *d, unsigned long gmfn)
{
- unsigned int i = gmfn - d->arch.hvm_domain.ioreq_gmfn.base;
+ unsigned long i = gmfn - d->arch.hvm_domain.ioreq_gmfn.base;
+ BUG_ON(i >= sizeof(d->arch.hvm_domain.ioreq_gmfn.mask) * 8);
clear_bit(i, &d->arch.hvm_domain.ioreq_gmfn.mask);
}
--
1.8.4
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