Messages in this thread | | | Subject | Re: [PATCH v2] swiotlb: avoid potential left shift overflow | From | Dongli Zhang <> | Date | Fri, 19 Aug 2022 06:44:05 -0700 |
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I also encountered this when sending out another version of the 64-bit swiotlb.
https://lore.kernel.org/all/20220609005553.30954-8-dongli.zhang@oracle.com/
Unfortunately, I could not find an environment (e.g., powerpc) to allocate more than 4G until swiotlb supports 64-bit.
Although xen supports 64-bit, but the hypervisor side limits the max to < 4G.
Dongli Zhang
On 8/19/22 1:45 AM, Chao Gao wrote: > The second operand passed to slot_addr() is declared as int or unsigned int > in all call sites. The left-shift to get the offset of a slot can overflow > if swiotlb size is larger than 4G. > > Convert the macro to an inline function and declare the second argument as > phys_addr_t to avoid the potential overflow. > > Fixes: 26a7e094783d ("swiotlb: refactor swiotlb_tbl_map_single") > Signed-off-by: Chao Gao <chao.gao@intel.com> > --- > kernel/dma/swiotlb.c | 5 ++++- > 1 file changed, 4 insertions(+), 1 deletion(-) > > diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c > index c5a9190b218f..41ea9fb3efe1 100644 > --- a/kernel/dma/swiotlb.c > +++ b/kernel/dma/swiotlb.c > @@ -579,7 +579,10 @@ static void swiotlb_bounce(struct device *dev, phys_addr_t tlb_addr, size_t size > } > } > > -#define slot_addr(start, idx) ((start) + ((idx) << IO_TLB_SHIFT)) > +static inline phys_addr_t slot_addr(phys_addr_t start, phys_addr_t idx) > +{ > + return start + (idx << IO_TLB_SHIFT); > +} > > /* > * Carefully handle integer overflow which can occur when boundary_mask == ~0UL. > > base-commit: 5c850d31880e00f063fa2a3746ba212c4bcc510f >
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