Hi Oleksandr,
Thank you for the patch.
On Monday, 21 August 2017 15:40:41 EEST Oleksandr Tyshchenko wrote:
> From: Oleksandr Tyshchenko <oleksandr_tyshche...@epam.com>
>
> In ipmmu_domain_init_context() we are trying to allocate context and
> if allocation fails we will call free_io_pgtable_ops(),
> but "domain->context_id" hasn't been initialized yet (likely it is 0
> because of kzalloc). Having the following call stack:
> free_io_pgtable_ops() -> io_pgtable_tlb_flush_all() ->
> ipmmu_tlb_flush_all() -> ipmmu_tlb_invalidate()
> we will get a mistaken cache flush for a context pointed by
> uninitialized "domain->context_id".
>
> So, set context_id to non-existent value (IPMMU_CTX_MAX) before calling
> free_io_pgtable_ops() and check it for a valid value (< IPMMU_CTX_MAX)
> before calling ipmmu_tlb_invalidate().
>
> Signed-off-by: Oleksandr Tyshchenko <oleksandr_tyshche...@epam.com>
> ---
> drivers/iommu/ipmmu-vmsa.c | 4 ++++
> 1 file changed, 4 insertions(+)
>
> diff --git a/drivers/iommu/ipmmu-vmsa.c b/drivers/iommu/ipmmu-vmsa.c
> index 2a38aa1..5b226c0 100644
> --- a/drivers/iommu/ipmmu-vmsa.c
> +++ b/drivers/iommu/ipmmu-vmsa.c
> @@ -303,6 +303,9 @@ static void ipmmu_tlb_flush_all(void *cookie)
> {
> struct ipmmu_vmsa_domain *domain = cookie;
>
> + if (domain->context_id >= IPMMU_CTX_MAX)
> + return;
> +
> ipmmu_tlb_invalidate(domain);
> }
>
> @@ -380,6 +383,7 @@ static int ipmmu_domain_init_context(struct
> ipmmu_vmsa_domain *domain) */
> ret = ipmmu_domain_allocate_context(domain->mmu, domain);
> if (ret == IPMMU_CTX_MAX) {
> + domain->context_id = IPMMU_CTX_MAX;
Wouldn't it make more sense to allocate the pgtable ops after initializing the
context (moving the ipmmu_domain_allocate_context() call to the very end of
the function) ? That way we would be less dependent on changes to pgtable ops
init/cleanup code that could require the context to be set up.
> free_io_pgtable_ops(domain->iop);
> return -EBUSY;
> }
--
Regards,
Laurent Pinchart
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