From: Roger Pau Monné Subject: [PATCH v5 6/9] vtd: don't assume addresses are aligned in sync_cache Current code in sync_cache assume that the address passed in is aligned to a cache line size. Fix the code to support passing in arbitrary addresses not necessarily aligned to a cache line size. This is part of XSA-321. Reported-by: Jan Beulich Signed-off-by: Roger Pau Monné Reviewed-by: Jan Beulich --- Changes since v5: - build fix Changes since v3: - Avoid one cast by using a subtraction. Changes since v2: - New in this version. --- xen/drivers/passthrough/vtd/iommu.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) --- a/xen/drivers/passthrough/vtd/iommu.c +++ b/xen/drivers/passthrough/vtd/iommu.c @@ -149,8 +149,8 @@ static int iommus_incoherent; static void sync_cache(const void *addr, unsigned int size) { - int i; - static unsigned int clflush_size = 0; + static unsigned long clflush_size = 0; + const void *end = addr + size; if ( !iommus_incoherent ) return; @@ -158,8 +158,9 @@ static void sync_cache(const void *addr, unsigned int size) if ( clflush_size == 0 ) clflush_size = get_cache_line_size(); - for ( i = 0; i < size; i += clflush_size ) - cacheline_flush((char *)addr + i); + addr -= (unsigned long)addr & (clflush_size - 1); + for ( ; addr < end; addr += clflush_size ) + cacheline_flush((char *)addr); } /* Allocate page table, return its machine address */