On 12/10/2022 2:31 AM, Tom Lendacky wrote:
> On 12/6/22 06:30, Rijo Thomas wrote:
>> For AMD Secure Processor (ASP) to map and access TEE ring buffer, the
>> ring buffer address sent by host to ASP must be a real physical
>> address and the pages must be physically contiguous.
>>
>> In a virtualized environment though, when the driver is running in a
>> guest VM, the pages allocated by __get_free_pages() may not be
>> contiguous in the host (or machine) physical address space. Guests
>> will see a guest (or pseudo) physical address and not the actual host
>> (or machine) physical address. The TEE running on ASP cannot decipher
>> pseudo physical addresses. It needs host or machine physical address.
>>
>> To resolve this problem, use DMA APIs for allocating buffers that must
>> be shared with TEE. This will ensure that the pages are contiguous in
>> host (or machine) address space. If the DMA handle is an IOVA,
>> translate it into a physical address before sending it to ASP.
>>
>> This patch also exports two APIs (one for buffer allocation and
>> another to free the buffer). This API can be used by AMD-TEE driver to
>> share buffers with TEE.
>>
>> Fixes: 33960acccfbd ("crypto: ccp - add TEE support for Raven Ridge")
>> Cc: Tom Lendacky <thomas.lendacky@xxxxxxx>
>> Cc: stable@xxxxxxxxxxxxxxx
>> Signed-off-by: Rijo Thomas <Rijo-john.Thomas@xxxxxxx>
>> Co-developed-by: Jeshwanth <JESHWANTHKUMAR.NK@xxxxxxx>
>> Signed-off-by: Jeshwanth <JESHWANTHKUMAR.NK@xxxxxxx>
>> Reviewed-by: Devaraj Rangasamy <Devaraj.Rangasamy@xxxxxxx>
>> ---
>> drivers/crypto/ccp/psp-dev.c | 6 +-
>> drivers/crypto/ccp/tee-dev.c | 116 ++++++++++++++++++++++-------------
>> drivers/crypto/ccp/tee-dev.h | 9 +--
>> include/linux/psp-tee.h | 47 ++++++++++++++
>> 4 files changed, 127 insertions(+), 51 deletions(-)
>>
>> diff --git a/drivers/crypto/ccp/psp-dev.c b/drivers/crypto/ccp/psp-dev.c
>> index c9c741ac8442..2b86158d7435 100644
>> --- a/drivers/crypto/ccp/psp-dev.c
>> +++ b/drivers/crypto/ccp/psp-dev.c
>> @@ -161,13 +161,13 @@ int psp_dev_init(struct sp_device *sp)
>> goto e_err;
>> }
>> + if (sp->set_psp_master_device)
>> + sp->set_psp_master_device(sp);
>> +
>
> This worries me a bit... if psp_init() fails, it may still be referenced as the master device. What's the reason for moving it?
Hmm. Okay, I see your point.
In psp_tee_alloc_dmabuf(), we call psp_get_master_device(). Without above change, psp_get_master_device() returns NULL.
I think in psp_dev_init(), we can add below error handling:
ret = psp_init(psp);
if (ret)
goto e_init;
...
e_init:
if (sp->clear_psp_master_device)
sp->clear_psp_master_device(sp);
Will this help address your concern?
>
>> ret = psp_init(psp);
>> if (ret)
>> goto e_irq;
>> - if (sp->set_psp_master_device)
>> - sp->set_psp_master_device(sp);
>> -
>> /* Enable interrupt */
>> iowrite32(-1, psp->io_regs + psp->vdata->inten_reg);
>> diff --git a/drivers/crypto/ccp/tee-dev.c b/drivers/crypto/ccp/tee-dev.c
>> index 5c9d47f3be37..1631d9851e54 100644
>> --- a/drivers/crypto/ccp/tee-dev.c
>> +++ b/drivers/crypto/ccp/tee-dev.c
>> @@ -12,8 +12,9 @@
>> #include <linux/mutex.h>
>> #include <linux/delay.h>
>> #include <linux/slab.h>
>> +#include <linux/dma-direct.h>
>> +#include <linux/iommu.h>
>> #include <linux/gfp.h>
>> -#include <linux/psp-sev.h>
>> #include <linux/psp-tee.h>
>> #include "psp-dev.h"
>> @@ -21,25 +22,64 @@
>> static bool psp_dead;
>> +struct dma_buffer *psp_tee_alloc_dmabuf(unsigned long size, gfp_t gfp)
>
> It looks like both calls to this use the same gfp_t values, you can probably eliminate from the call and just specify them in here.
>
Okay, I will remove gfp_t flag from the function argument.
>> +{
>> + struct psp_device *psp = psp_get_master_device();
>> + struct dma_buffer *dma_buf;
>> + struct iommu_domain *dom;
>> +
>> + if (!psp || !size)
>> + return NULL;
>> +
>> + dma_buf = kzalloc(sizeof(*dma_buf), GFP_KERNEL);
>> + if (!dma_buf)
>> + return NULL;
>> +
>> + dma_buf->vaddr = dma_alloc_coherent(psp->dev, size, &dma_buf->dma, gfp);
>> + if (!dma_buf->vaddr || !dma_buf->dma) {
>
> I don't think you can have one of these be NULL without both being NULL, but I guess it doesn't hurt to check.
>
Okay, we will keep both checks for now.
>> + kfree(dma_buf);
>> + return NULL;
>> + }
>> +
>> + dma_buf->size = size;
>> + > + dom = iommu_get_domain_for_dev(psp->dev);
>> + if (dom)
>
> You need a nice comment above this all explaining that. I guess you're using the presence of a domain to determine whether you're running on bare-metal vs within a hypervisor? I'm not sure what will happen if the guest ever gets an emulated IOMMU...
Sure we will add a comment.
We are not trying to determive bare-metal vs hypervisor here, but determine whether DMA handle returned by dma_alloc_coherent() is an IOVA or not.
If the address is an IOVA, we convert IOVA to physical address using iommu_iova_to_phys(). This was our intention.
>
>> + dma_buf->paddr = iommu_iova_to_phys(dom, dma_buf->dma);
>
> If you're just looking to get the physical address, why not just to an __pa(dma_buf->vaddr)?
>
> Also, paddr might not be the best name, since it isn't always a physical address, but I can't really think of something right now.
>
We can use __pa(dma_buf->vaddr) only on bare-metal. In hypervisor, __pa(dma_buf->vaddr) gives pseudo-physical address; pseudo-physical address cannot be understood by ASP.
ASP needs real physical address (aka machine address). Please see commit message.
We chose the name paddr, since it's a (real) physical address that we want to send across to ASP. I am not sure, why you say - it isn't always a physical address.
Thanks,
Rijo
> Thanks,
> Tom
>
>> + else
>> + dma_buf->paddr = dma_buf->dma;
>> +
>> + return dma_buf;
>> +}
>> +EXPORT_SYMBOL(psp_tee_alloc_dmabuf);
>> +
>> +void psp_tee_free_dmabuf(struct dma_buffer *dma_buf)
>> +{
>> + struct psp_device *psp = psp_get_master_device();
>> +
>> + if (!psp || !dma_buf)
>> + return;
>> +
>> + dma_free_coherent(psp->dev, dma_buf->size,
>> + dma_buf->vaddr, dma_buf->dma);
>> +
>> + kfree(dma_buf);
>> +}
>> +EXPORT_SYMBOL(psp_tee_free_dmabuf);
>> +
>> static int tee_alloc_ring(struct psp_tee_device *tee, int ring_size)
>> {
>> struct ring_buf_manager *rb_mgr = &tee->rb_mgr;
>> - void *start_addr;
>> if (!ring_size)
>> return -EINVAL;
>> - /* We need actual physical address instead of DMA address, since
>> - * Trusted OS running on AMD Secure Processor will map this region
>> - */
>> - start_addr = (void *)__get_free_pages(GFP_KERNEL, get_order(ring_size));
>> - if (!start_addr)
>> + rb_mgr->ring_buf = psp_tee_alloc_dmabuf(ring_size,
>> + GFP_KERNEL | __GFP_ZERO);
>> + if (!rb_mgr->ring_buf) {
>> + dev_err(tee->dev, "ring allocation failed\n");
>> return -ENOMEM;
>> -
>> - memset(start_addr, 0x0, ring_size);
>> - rb_mgr->ring_start = start_addr;
>> - rb_mgr->ring_size = ring_size;
>> - rb_mgr->ring_pa = __psp_pa(start_addr);
>> + }
>> mutex_init(&rb_mgr->mutex);
>> return 0;
>> @@ -49,15 +89,8 @@ static void tee_free_ring(struct psp_tee_device *tee)
>> {
>> struct ring_buf_manager *rb_mgr = &tee->rb_mgr;
>> - if (!rb_mgr->ring_start)
>> - return;
>> + psp_tee_free_dmabuf(rb_mgr->ring_buf);
>> - free_pages((unsigned long)rb_mgr->ring_start,
>> - get_order(rb_mgr->ring_size));
>> -
>> - rb_mgr->ring_start = NULL;
>> - rb_mgr->ring_size = 0;
>> - rb_mgr->ring_pa = 0;
>> mutex_destroy(&rb_mgr->mutex);
>> }
>> @@ -81,35 +114,36 @@ static int tee_wait_cmd_poll(struct psp_tee_device *tee, unsigned int timeout,
>> return -ETIMEDOUT;
>> }
>> -static
>> -struct tee_init_ring_cmd *tee_alloc_cmd_buffer(struct psp_tee_device *tee)
>> +struct dma_buffer *tee_alloc_cmd_buffer(struct psp_tee_device *tee)
>> {
>> struct tee_init_ring_cmd *cmd;
>> + struct dma_buffer *cmd_buffer;
>> - cmd = kzalloc(sizeof(*cmd), GFP_KERNEL);
>> - if (!cmd)
>> + cmd_buffer = psp_tee_alloc_dmabuf(sizeof(*cmd),
>> + GFP_KERNEL | __GFP_ZERO);
>> + if (!cmd_buffer)
>> return NULL;
>> - cmd->hi_addr = upper_32_bits(tee->rb_mgr.ring_pa);
>> - cmd->low_addr = lower_32_bits(tee->rb_mgr.ring_pa);
>> - cmd->size = tee->rb_mgr.ring_size;
>> + cmd = (struct tee_init_ring_cmd *)cmd_buffer->vaddr;
>> + cmd->hi_addr = upper_32_bits(tee->rb_mgr.ring_buf->paddr);
>> + cmd->low_addr = lower_32_bits(tee->rb_mgr.ring_buf->paddr);
>> + cmd->size = tee->rb_mgr.ring_buf->size;
>> dev_dbg(tee->dev, "tee: ring address: high = 0x%x low = 0x%x size = %u\n",
>> cmd->hi_addr, cmd->low_addr, cmd->size);
>> - return cmd;
>> + return cmd_buffer;
>> }
>> -static inline void tee_free_cmd_buffer(struct tee_init_ring_cmd *cmd)
>> +static inline void tee_free_cmd_buffer(struct dma_buffer *cmd_buffer)
>> {
>> - kfree(cmd);
>> + psp_tee_free_dmabuf(cmd_buffer);
>> }
>> static int tee_init_ring(struct psp_tee_device *tee)
>> {
>> int ring_size = MAX_RING_BUFFER_ENTRIES * sizeof(struct tee_ring_cmd);
>> - struct tee_init_ring_cmd *cmd;
>> - phys_addr_t cmd_buffer;
>> + struct dma_buffer *cmd_buffer;
>> unsigned int reg;
>> int ret;
>> @@ -123,21 +157,19 @@ static int tee_init_ring(struct psp_tee_device *tee)
>> tee->rb_mgr.wptr = 0;
>> - cmd = tee_alloc_cmd_buffer(tee);
>> - if (!cmd) {
>> + cmd_buffer = tee_alloc_cmd_buffer(tee);
>> + if (!cmd_buffer) {
>> tee_free_ring(tee);
>> return -ENOMEM;
>> }
>> - cmd_buffer = __psp_pa((void *)cmd);
>> -
>> /* Send command buffer details to Trusted OS by writing to
>> * CPU-PSP message registers
>> */
>> - iowrite32(lower_32_bits(cmd_buffer),
>> + iowrite32(lower_32_bits(cmd_buffer->paddr),
>> tee->io_regs + tee->vdata->cmdbuff_addr_lo_reg);
>> - iowrite32(upper_32_bits(cmd_buffer),
>> + iowrite32(upper_32_bits(cmd_buffer->paddr),
>> tee->io_regs + tee->vdata->cmdbuff_addr_hi_reg);
>> iowrite32(TEE_RING_INIT_CMD,
>> tee->io_regs + tee->vdata->cmdresp_reg);
>> @@ -157,7 +189,7 @@ static int tee_init_ring(struct psp_tee_device *tee)
>> }
>> free_buf:
>> - tee_free_cmd_buffer(cmd);
>> + tee_free_cmd_buffer(cmd_buffer);
>> return ret;
>> }
>> @@ -167,7 +199,7 @@ static void tee_destroy_ring(struct psp_tee_device *tee)
>> unsigned int reg;
>> int ret;
>> - if (!tee->rb_mgr.ring_start)
>> + if (!tee->rb_mgr.ring_buf->vaddr)
>> return;
>> if (psp_dead)
>> @@ -256,7 +288,7 @@ static int tee_submit_cmd(struct psp_tee_device *tee, enum tee_cmd_id cmd_id,
>> do {
>> /* Get pointer to ring buffer command entry */
>> cmd = (struct tee_ring_cmd *)
>> - (tee->rb_mgr.ring_start + tee->rb_mgr.wptr);
>> + (tee->rb_mgr.ring_buf->vaddr + tee->rb_mgr.wptr);
>> rptr = ioread32(tee->io_regs + tee->vdata->ring_rptr_reg);
>> @@ -305,7 +337,7 @@ static int tee_submit_cmd(struct psp_tee_device *tee, enum tee_cmd_id cmd_id,
>> /* Update local copy of write pointer */
>> tee->rb_mgr.wptr += sizeof(struct tee_ring_cmd);
>> - if (tee->rb_mgr.wptr >= tee->rb_mgr.ring_size)
>> + if (tee->rb_mgr.wptr >= tee->rb_mgr.ring_buf->size)
>> tee->rb_mgr.wptr = 0;
>> /* Trigger interrupt to Trusted OS */
>> diff --git a/drivers/crypto/ccp/tee-dev.h b/drivers/crypto/ccp/tee-dev.h
>> index 49d26158b71e..9238487ee8bf 100644
>> --- a/drivers/crypto/ccp/tee-dev.h
>> +++ b/drivers/crypto/ccp/tee-dev.h
>> @@ -16,6 +16,7 @@
>> #include <linux/device.h>
>> #include <linux/mutex.h>
>> +#include <linux/psp-tee.h>
>> #define TEE_DEFAULT_TIMEOUT 10
>> #define MAX_BUFFER_SIZE 988
>> @@ -48,17 +49,13 @@ struct tee_init_ring_cmd {
>> /**
>> * struct ring_buf_manager - Helper structure to manage ring buffer.
>> - * @ring_start: starting address of ring buffer
>> - * @ring_size: size of ring buffer in bytes
>> - * @ring_pa: physical address of ring buffer
>> * @wptr: index to the last written entry in ring buffer
>> + * @ring_buf: ring buffer allocated using DMA api
>> */
>> struct ring_buf_manager {
>> struct mutex mutex; /* synchronizes access to ring buffer */
>> - void *ring_start;
>> - u32 ring_size;
>> - phys_addr_t ring_pa;
>> u32 wptr;
>> + struct dma_buffer *ring_buf;
>> };
>> struct psp_tee_device {
>> diff --git a/include/linux/psp-tee.h b/include/linux/psp-tee.h
>> index cb0c95d6d76b..c0fa922f24d4 100644
>> --- a/include/linux/psp-tee.h
>> +++ b/include/linux/psp-tee.h
>> @@ -13,6 +13,7 @@
>> #include <linux/types.h>
>> #include <linux/errno.h>
>> +#include <linux/dma-mapping.h>
>> /* This file defines the Trusted Execution Environment (TEE) interface commands
>> * and the API exported by AMD Secure Processor driver to communicate with
>> @@ -40,6 +41,20 @@ enum tee_cmd_id {
>> TEE_CMD_ID_UNMAP_SHARED_MEM,
>> };
>> +/**
>> + * struct dma_buffer - Structure for a DMA buffer.
>> + * @dma: DMA buffer address
>> + * @paddr: Physical address of DMA buffer
>> + * @vaddr: CPU virtual address of DMA buffer
>> + * @size: Size of DMA buffer in bytes
>> + */
>> +struct dma_buffer {
>> + dma_addr_t dma;
>> + phys_addr_t paddr;
>> + void *vaddr;
>> + unsigned long size;
>> +};
>> +
>> #ifdef CONFIG_CRYPTO_DEV_SP_PSP
>> /**
>> * psp_tee_process_cmd() - Process command in Trusted Execution Environment
>> @@ -75,6 +90,28 @@ int psp_tee_process_cmd(enum tee_cmd_id cmd_id, void *buf, size_t len,
>> */
>> int psp_check_tee_status(void);
>> +/**
>> + * psp_tee_alloc_dmabuf() - Allocates memory of requested size and flags using
>> + * dma_alloc_coherent() API.
>> + *
>> + * This function can be used to allocate a shared memory region between the
>> + * host and PSP TEE.
>> + *
>> + * Returns:
>> + * non-NULL a valid pointer to struct dma_buffer
>> + * NULL on failure
>> + */
>> +struct dma_buffer *psp_tee_alloc_dmabuf(unsigned long size, gfp_t gfp);
>> +
>> +/**
>> + * psp_tee_free_dmabuf() - Deallocates memory using dma_free_coherent() API.
>> + *
>> + * This function can be used to release shared memory region between host
>> + * and PSP TEE.
>> + *
>> + */
>> +void psp_tee_free_dmabuf(struct dma_buffer *dma_buffer);
>> +
>> #else /* !CONFIG_CRYPTO_DEV_SP_PSP */
>> static inline int psp_tee_process_cmd(enum tee_cmd_id cmd_id, void *buf,
>> @@ -87,5 +124,15 @@ static inline int psp_check_tee_status(void)
>> {
>> return -ENODEV;
>> }
>> +
>> +static inline
>> +struct dma_buffer *psp_tee_alloc_dmabuf(unsigned long size, gfp_t gfp)
>> +{
>> + return NULL;
>> +}
>> +
>> +static inline void psp_tee_free_dmabuf(struct dma_buffer *dma_buffer)
>> +{
>> +}
>> #endif /* CONFIG_CRYPTO_DEV_SP_PSP */
>> #endif /* __PSP_TEE_H_ */
