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Commit 519c31ba authored by Joerg Roedel's avatar Joerg Roedel Committed by Ingo Molnar
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x86, AMD IOMMU: use status bit instead of memory write-back for completion wait 



Signed-off-by: default avatarJoerg Roedel <joerg.roedel@amd.com>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent b635acec

arch/x86/kernel/amd_iommu.c

+10 −7
Original line number Diff line number Diff line
@@ -101,16 +101,13 @@ static int iommu_queue_command(struct amd_iommu *iommu, struct iommu_cmd *cmd) 
 */

static int iommu_completion_wait(struct amd_iommu *iommu)

{

	int ret;

	int ret, ready = 0;

	unsigned status = 0;

	struct iommu_cmd cmd;

	volatile u64 ready = 0;

	unsigned long ready_phys = virt_to_phys(&ready);

	unsigned long i = 0;



	memset(&cmd, 0, sizeof(cmd));

	cmd.data[0] = LOW_U32(ready_phys) | CMD_COMPL_WAIT_STORE_MASK;

	cmd.data[1] = upper_32_bits(ready_phys);

	cmd.data[2] = 1; /* value written to 'ready' */

	cmd.data[0] = CMD_COMPL_WAIT_INT_MASK;

	CMD_SET_TYPE(&cmd, CMD_COMPL_WAIT);



	iommu->need_sync = 0;
@@ -122,9 +119,15 @@ static int iommu_completion_wait(struct amd_iommu *iommu) 


	while (!ready && (i < EXIT_LOOP_COUNT)) {

		++i;

		cpu_relax();

		/* wait for the bit to become one */

		status = readl(iommu->mmio_base + MMIO_STATUS_OFFSET);

		ready = status & MMIO_STATUS_COM_WAIT_INT_MASK;

	}



	/* set bit back to zero */

	status &= ~MMIO_STATUS_COM_WAIT_INT_MASK;

	writel(status, iommu->mmio_base + MMIO_STATUS_OFFSET);



	if (unlikely((i == EXIT_LOOP_COUNT) && printk_ratelimit()))

		printk(KERN_WARNING "AMD IOMMU: Completion wait loop failed\n");

include/asm-x86/amd_iommu_types.h

+4 −0
Original line number Diff line number Diff line
@@ -69,6 +69,9 @@ 
#define MMIO_EVT_TAIL_OFFSET	0x2018

#define MMIO_STATUS_OFFSET	0x2020



/* MMIO status bits */

#define MMIO_STATUS_COM_WAIT_INT_MASK	0x04



/* feature control bits */

#define CONTROL_IOMMU_EN        0x00ULL

#define CONTROL_HT_TUN_EN       0x01ULL
@@ -89,6 +92,7 @@ 
#define CMD_INV_IOMMU_PAGES     0x03



#define CMD_COMPL_WAIT_STORE_MASK	0x01

#define CMD_COMPL_WAIT_INT_MASK		0x02

#define CMD_INV_IOMMU_PAGES_SIZE_MASK	0x01

#define CMD_INV_IOMMU_PAGES_PDE_MASK	0x02