| lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
|
Open Source and information security mailing list archives
| ||
|
Date: Thu, 7 Apr 2011 15:29:59 +0200
From: Joerg Roedel <joerg.roedel@....com>
To: <iommu@...ts.linux-foundation.org>
CC: <linux-kernel@...r.kernel.org>, Joerg Roedel <joerg.roedel@....com>
Subject: [PATCH 4/9] x86/amd-iommu: Cleanup completion-wait handling
This patch cleans up the implementation of completion-wait
command sending. It also switches the completion indicator
from the MMIO bit to a memory store which can be checked
without IOMMU locking.
As a side effect this patch makes the __iommu_queue_command
function obsolete and so it is removed too.
Signed-off-by: Joerg Roedel <joerg.roedel@....com>
---
arch/x86/kernel/amd_iommu.c | 107 +++++++++++-------------------------------
1 files changed, 28 insertions(+), 79 deletions(-)
diff --git a/arch/x86/kernel/amd_iommu.c b/arch/x86/kernel/amd_iommu.c
index f8ec28e..073c64b 100644
--- a/arch/x86/kernel/amd_iommu.c
+++ b/arch/x86/kernel/amd_iommu.c
@@ -25,6 +25,7 @@
#include <linux/dma-mapping.h>
#include <linux/iommu-helper.h>
#include <linux/iommu.h>
+#include <linux/delay.h>
#include <asm/proto.h>
#include <asm/iommu.h>
#include <asm/gart.h>
@@ -34,7 +35,7 @@
#define CMD_SET_TYPE(cmd, t) ((cmd)->data[1] |= ((t) << 28))
-#define EXIT_LOOP_COUNT 10000000
+#define LOOP_TIMEOUT 100000
static DEFINE_RWLOCK(amd_iommu_devtable_lock);
@@ -383,10 +384,14 @@ irqreturn_t amd_iommu_int_handler(int irq, void *data)
*
****************************************************************************/
-static void build_completion_wait(struct iommu_cmd *cmd)
+static void build_completion_wait(struct iommu_cmd *cmd, u64 address)
{
+ WARN_ON(address & 0x7ULL);
+
memset(cmd, 0, sizeof(*cmd));
- cmd->data[0] = CMD_COMPL_WAIT_INT_MASK;
+ cmd->data[0] = lower_32_bits(__pa(address)) | CMD_COMPL_WAIT_STORE_MASK;
+ cmd->data[1] = upper_32_bits(__pa(address));
+ cmd->data[2] = 1;
CMD_SET_TYPE(cmd, CMD_COMPL_WAIT);
}
@@ -432,12 +437,14 @@ 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.
*/
-static int __iommu_queue_command(struct amd_iommu *iommu, struct iommu_cmd *cmd)
+static int iommu_queue_command(struct amd_iommu *iommu, struct iommu_cmd *cmd)
{
+ unsigned long flags;
u32 tail, head;
u8 *target;
WARN_ON(iommu->cmd_buf_size & CMD_BUFFER_UNINITIALIZED);
+ 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));
@@ -446,99 +453,41 @@ static int __iommu_queue_command(struct amd_iommu *iommu, struct iommu_cmd *cmd)
if (tail == head)
return -ENOMEM;
writel(tail, iommu->mmio_base + MMIO_CMD_TAIL_OFFSET);
-
- return 0;
-}
-
-/*
- * General queuing function for commands. Takes iommu->lock and calls
- * __iommu_queue_command().
- */
-static int iommu_queue_command(struct amd_iommu *iommu, struct iommu_cmd *cmd)
-{
- unsigned long flags;
- int ret;
-
- spin_lock_irqsave(&iommu->lock, flags);
- ret = __iommu_queue_command(iommu, cmd);
- if (!ret)
- iommu->need_sync = true;
+ iommu->need_sync = true;
spin_unlock_irqrestore(&iommu->lock, flags);
- return ret;
-}
-
-/*
- * This function waits until an IOMMU has completed a completion
- * wait command
- */
-static void __iommu_wait_for_completion(struct amd_iommu *iommu)
-{
- int ready = 0;
- unsigned status = 0;
- unsigned long i = 0;
-
- INC_STATS_COUNTER(compl_wait);
-
- while (!ready && (i < EXIT_LOOP_COUNT)) {
- ++i;
- /* 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))
- iommu->reset_in_progress = true;
+ return 0;
}
/*
* This function queues a completion wait command into the command
* buffer of an IOMMU
*/
-static int __iommu_completion_wait(struct amd_iommu *iommu)
-{
- struct iommu_cmd cmd;
-
- build_completion_wait(&cmd);
-
- return __iommu_queue_command(iommu, &cmd);
-}
-
-/*
- * This function is called whenever we need to ensure that the IOMMU has
- * completed execution of all commands we sent. It sends a
- * COMPLETION_WAIT command and waits for it to finish. The IOMMU informs
- * us about that by writing a value to a physical address we pass with
- * the command.
- */
static int iommu_completion_wait(struct amd_iommu *iommu)
{
- int ret = 0;
- unsigned long flags;
-
- spin_lock_irqsave(&iommu->lock, flags);
+ struct iommu_cmd cmd;
+ volatile u64 sem = 0;
+ int ret, i = 0;
if (!iommu->need_sync)
- goto out;
-
- ret = __iommu_completion_wait(iommu);
+ return 0;
- iommu->need_sync = false;
+ build_completion_wait(&cmd, (u64)&sem);
+ ret = iommu_queue_command(iommu, &cmd);
if (ret)
- goto out;
-
- __iommu_wait_for_completion(iommu);
+ return ret;
-out:
- spin_unlock_irqrestore(&iommu->lock, flags);
+ while (sem == 0 && i < LOOP_TIMEOUT) {
+ udelay(1);
+ i += 1;
+ }
- if (iommu->reset_in_progress)
+ if (i == LOOP_TIMEOUT) {
+ pr_alert("AMD-Vi: Completion-Wait loop timed out\n");
+ iommu->reset_in_progress = true;
reset_iommu_command_buffer(iommu);
+ }
return 0;
}
--
1.7.1
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
Powered by blists - more mailing lists