x86/amd-iommu: Improve handling of full command buffer (ac0ea6e9) · Commits · 戴 / test

arch/x86/kernel/amd_iommu.c

+65 −23

Original line number	Diff line number	Diff line
		@@ -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);
		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);
		}

		/*

Admin message