diff options
| -rw-r--r-- | arch/x86/kernel/amd_iommu.c | 88 |
1 files changed, 65 insertions, 23 deletions
diff --git a/arch/x86/kernel/amd_iommu.c b/arch/x86/kernel/amd_iommu.c index 9d66b2092ae1..75c7f8c3fe12 100644 --- a/arch/x86/kernel/amd_iommu.c +++ b/arch/x86/kernel/amd_iommu.c @@ -381,6 +381,39 @@ irqreturn_t amd_iommu_int_handler(int irq, void *data) * ****************************************************************************/ +static int wait_on_sem(volatile u64 *sem) +{ + int i = 0; + + while (*sem == 0 && i < LOOP_TIMEOUT) { + udelay(1); + i += 1; + } + + if (i == LOOP_TIMEOUT) { + pr_alert("AMD-Vi: Completion-Wait loop timed out\n"); + return -EIO; + } + + return 0; +} + +static void copy_cmd_to_buffer(struct amd_iommu *iommu, + struct iommu_cmd *cmd, + u32 tail) +{ + u8 *target; + + target = iommu->cmd_buf + tail; + tail = (tail + sizeof(*cmd)) % iommu->cmd_buf_size; + + /* Copy command to buffer */ + memcpy(target, cmd, sizeof(*cmd)); + + /* Tell the IOMMU about it */ + writel(tail, iommu->mmio_base + MMIO_CMD_TAIL_OFFSET); +} + static void build_completion_wait(struct iommu_cmd *cmd, u64 address) { WARN_ON(address & 0x7ULL); @@ -432,25 +465,44 @@ static void build_inv_iommu_pages(struct iommu_cmd *cmd, u64 address, /* * Writes the command to the IOMMUs command buffer and informs the - * hardware about the new command. Must be called with iommu->lock held. + * hardware about the new command. */ static int iommu_queue_command(struct amd_iommu *iommu, struct iommu_cmd *cmd) { + u32 left, tail, head, next_tail; unsigned long flags; - u32 tail, head; - u8 *target; WARN_ON(iommu->cmd_buf_size & CMD_BUFFER_UNINITIALIZED); + +again: spin_lock_irqsave(&iommu->lock, flags); - tail = readl(iommu->mmio_base + MMIO_CMD_TAIL_OFFSET); - target = iommu->cmd_buf + tail; - memcpy_toio(target, cmd, sizeof(*cmd)); - tail = (tail + sizeof(*cmd)) % iommu->cmd_buf_size; - head = readl(iommu->mmio_base + MMIO_CMD_HEAD_OFFSET); - if (tail == head) - return -ENOMEM; - writel(tail, iommu->mmio_base + MMIO_CMD_TAIL_OFFSET); + + head = readl(iommu->mmio_base + MMIO_CMD_HEAD_OFFSET); + tail = readl(iommu->mmio_base + MMIO_CMD_TAIL_OFFSET); + next_tail = (tail + sizeof(*cmd)) % iommu->cmd_buf_size; + left = (head - next_tail) % iommu->cmd_buf_size; + + if (left <= 2) { + struct iommu_cmd sync_cmd; + volatile u64 sem = 0; + int ret; + + build_completion_wait(&sync_cmd, (u64)&sem); + copy_cmd_to_buffer(iommu, &sync_cmd, tail); + + spin_unlock_irqrestore(&iommu->lock, flags); + + if ((ret = wait_on_sem(&sem)) != 0) + return ret; + + goto again; + } + + copy_cmd_to_buffer(iommu, cmd, tail); + + /* We need to sync now to make sure all commands are processed */ iommu->need_sync = true; + spin_unlock_irqrestore(&iommu->lock, flags); return 0; @@ -464,7 +516,7 @@ static int iommu_completion_wait(struct amd_iommu *iommu) { struct iommu_cmd cmd; volatile u64 sem = 0; - int ret, i = 0; + int ret; if (!iommu->need_sync) return 0; @@ -475,17 +527,7 @@ static int iommu_completion_wait(struct amd_iommu *iommu) if (ret) return ret; - while (sem == 0 && i < LOOP_TIMEOUT) { - udelay(1); - i += 1; - } - - if (i == LOOP_TIMEOUT) { - pr_alert("AMD-Vi: Completion-Wait loop timed out\n"); - ret = -EIO; - } - - return 0; + return wait_on_sem(&sem); } /* |