Re: [PATCH V3 05/10] remoteproc: qcom_q6v5_mss: Use a carveout to authenticate modem headers

Sibi Sankar
2023-01-11T12:29:20Z

Hey Mani,

Thanks for taking time to review the series.

On 1/11/23 17:24, Manivannan Sadhasivam wrote:
> On Wed, Jan 11, 2023 at 05:13:32PM +0530, Sibi Sankar wrote:
>> Any access to the dynamically allocated metadata region by the application
>> processor after assigning it to the remote Q6 will result in a XPU
>> violation. Fix this by replacing the dynamically allocated memory region
>> with a no-map carveout and unmap the modem metadata memory region before
>> passing control to the remote Q6.
>>
>> Reported-and-tested-by: Amit Pundir <amit.pundir@linaro.org>
>> Fixes: 6c5a9dc2481b ("remoteproc: qcom: Make secure world call for mem ownership switch")
>> Signed-off-by: Sibi Sankar <quic_sibis@quicinc.com>
>
> Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
>
>> ---
>>
>> v3:
>> * Drop revert no_kernel_mapping since it's already on the list [Mani]
>
> I thought you are going to include Christoph's patch into your series. That way
> all the patches will be in the same series, makig life easier for Bjorn.
>

Since there were multiple patches in Christoph's original series, I
decided I'll just drop the revert and have it depends on instead.

> Thanks,
> Mani
>
>> * kfree metadata from the branch for parity
>>
>> drivers/remoteproc/qcom_q6v5_mss.c | 48 ++++++++++++++++++++++++++----
>> 1 file changed, 42 insertions(+), 6 deletions(-)
>>
>> diff --git a/drivers/remoteproc/qcom_q6v5_mss.c b/drivers/remoteproc/qcom_q6v5_mss.c
>> index e2f765f87ec9..e25d44e20ae7 100644
>> --- a/drivers/remoteproc/qcom_q6v5_mss.c
>> +++ b/drivers/remoteproc/qcom_q6v5_mss.c
>> @@ -215,6 +215,7 @@ struct q6v5 {
>> size_t mba_size;
>> size_t dp_size;
>>
>> + phys_addr_t mdata_phys;
>> phys_addr_t mpss_phys;
>> phys_addr_t mpss_reloc;
>> size_t mpss_size;
>> @@ -973,15 +974,29 @@ static int q6v5_mpss_init_image(struct q6v5 *qproc, const struct firmware *fw,
>> if (IS_ERR(metadata))
>> return PTR_ERR(metadata);
>>
>> - ptr = dma_alloc_attrs(qproc->dev, size, &phys, GFP_KERNEL, dma_attrs);
>> - if (!ptr) {
>> - kfree(metadata);
>> - dev_err(qproc->dev, "failed to allocate mdt buffer\n");
>> - return -ENOMEM;
>> + if (qproc->mdata_phys) {
>> + phys = qproc->mdata_phys;
>> + ptr = memremap(qproc->mdata_phys, size, MEMREMAP_WC);
>> + if (!ptr) {
>> + kfree(metadata);
>> + dev_err(qproc->dev, "unable to map memory region: %pa+%zx\n",
>> + &qproc->mdata_phys, size);
>> + return -EBUSY;
>> + }
>> + } else {
>> + ptr = dma_alloc_attrs(qproc->dev, size, &phys, GFP_KERNEL, dma_attrs);
>> + if (!ptr) {
>> + kfree(metadata);
>> + dev_err(qproc->dev, "failed to allocate mdt buffer\n");
>> + return -ENOMEM;
>> + }
>> }
>>
>> memcpy(ptr, metadata, size);
>>
>> + if (qproc->mdata_phys)
>> + memunmap(ptr);
>> +
>> /* Hypervisor mapping to access metadata by modem */
>> mdata_perm = BIT(QCOM_SCM_VMID_HLOS);
>> ret = q6v5_xfer_mem_ownership(qproc, &mdata_perm, false, true,
>> @@ -1010,7 +1025,8 @@ static int q6v5_mpss_init_image(struct q6v5 *qproc, const struct firmware *fw,
>> "mdt buffer not reclaimed system may become unstable\n");
>>
>> free_dma_attrs:
>> - dma_free_attrs(qproc->dev, size, ptr, phys, dma_attrs);
>> + if (!qproc->mdata_phys)
>> + dma_free_attrs(qproc->dev, size, ptr, phys, dma_attrs);
>> kfree(metadata);
>>
>> return ret < 0 ? ret : 0;
>> @@ -1893,6 +1909,26 @@ static int q6v5_alloc_memory_region(struct q6v5 *qproc)
>> qproc->mpss_phys = qproc->mpss_reloc = r.start;
>> qproc->mpss_size = resource_size(&r);
>>
>> + if (!child) {
>> + node = of_parse_phandle(qproc->dev->of_node, "memory-region", 2);
>> + } else {
>> + child = of_get_child_by_name(qproc->dev->of_node, "metadata");
>> + node = of_parse_phandle(child, "memory-region", 0);
>> + of_node_put(child);
>> + }
>> +
>> + if (!node)
>> + return 0;
>> +
>> + ret = of_address_to_resource(node, 0, &r);
>> + of_node_put(node);
>> + if (ret) {
>> + dev_err(qproc->dev, "unable to resolve metadata region\n");
>> + return ret;
>> + }
>> +
>> + qproc->mdata_phys = r.start;
>> +
>> return 0;
>> }
>>
>> --
>> 2.17.1
>>
>