linux-kernel - [PATCH 1/5] iommu/amd: restore GA log/tail pointer on host resume

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Date:   Tue, 23 Nov 2021 18:10:34 +0200
From:   Maxim Levitsky <mlevitsk@...hat.com>
To:     linux-kernel@...r.kernel.org
Cc:     David Woodhouse <dwmw@...zon.co.uk>,
        Suravee Suthikulpanit <suravee.suthikulpanit@....com>,
        Joerg Roedel <joro@...tes.org>,
        Thomas Gleixner <tglx@...utronix.de>,
        iommu@...ts.linux-foundation.org (open list:AMD IOMMU (AMD-VI)),
        Will Deacon <will@...nel.org>,
        Maxim Levitsky <mlevitsk@...hat.com>
Subject: [PATCH 1/5] iommu/amd: restore GA log/tail pointer on host resume

This will give IOMMU GA log a chance to work after resume
from s3/s4.

Fixes: 8bda0cfbdc1a6 ("iommu/amd: Detect and initialize guest vAPIC log")

Signed-off-by: Maxim Levitsky <mlevitsk@...hat.com>
---
 drivers/iommu/amd/init.c | 31 +++++++++++++++----------------
 1 file changed, 15 insertions(+), 16 deletions(-)

diff --git a/drivers/iommu/amd/init.c b/drivers/iommu/amd/init.c
index 1eacd43cb4368..8dae85fcfc2eb 100644
--- a/drivers/iommu/amd/init.c
+++ b/drivers/iommu/amd/init.c
@@ -806,16 +806,27 @@ static int iommu_ga_log_enable(struct amd_iommu *iommu)
 {
 #ifdef CONFIG_IRQ_REMAP
 	u32 status, i;
+	u64 entry;
 
 	if (!iommu->ga_log)
 		return -EINVAL;
 
-	status = readl(iommu->mmio_base + MMIO_STATUS_OFFSET);
-
 	/* Check if already running */
-	if (status & (MMIO_STATUS_GALOG_RUN_MASK))
+	status = readl(iommu->mmio_base + MMIO_STATUS_OFFSET);
+	if (WARN_ON(status & (MMIO_STATUS_GALOG_RUN_MASK)))
 		return 0;
 
+	entry = iommu_virt_to_phys(iommu->ga_log) | GA_LOG_SIZE_512;
+	memcpy_toio(iommu->mmio_base + MMIO_GA_LOG_BASE_OFFSET,
+		    &entry, sizeof(entry));
+	entry = (iommu_virt_to_phys(iommu->ga_log_tail) &
+		 (BIT_ULL(52)-1)) & ~7ULL;
+	memcpy_toio(iommu->mmio_base + MMIO_GA_LOG_TAIL_OFFSET,
+		    &entry, sizeof(entry));
+	writel(0x00, iommu->mmio_base + MMIO_GA_HEAD_OFFSET);
+	writel(0x00, iommu->mmio_base + MMIO_GA_TAIL_OFFSET);
+
+
 	iommu_feature_enable(iommu, CONTROL_GAINT_EN);
 	iommu_feature_enable(iommu, CONTROL_GALOG_EN);
 
@@ -825,7 +836,7 @@ static int iommu_ga_log_enable(struct amd_iommu *iommu)
 			break;
 	}
 
-	if (i >= LOOP_TIMEOUT)
+	if (WARN_ON(i >= LOOP_TIMEOUT))
 		return -EINVAL;
 #endif /* CONFIG_IRQ_REMAP */
 	return 0;
@@ -834,8 +845,6 @@ static int iommu_ga_log_enable(struct amd_iommu *iommu)
 static int iommu_init_ga_log(struct amd_iommu *iommu)
 {
 #ifdef CONFIG_IRQ_REMAP
-	u64 entry;
-
 	if (!AMD_IOMMU_GUEST_IR_VAPIC(amd_iommu_guest_ir))
 		return 0;
 
@@ -849,16 +858,6 @@ static int iommu_init_ga_log(struct amd_iommu *iommu)
 	if (!iommu->ga_log_tail)
 		goto err_out;
 
-	entry = iommu_virt_to_phys(iommu->ga_log) | GA_LOG_SIZE_512;
-	memcpy_toio(iommu->mmio_base + MMIO_GA_LOG_BASE_OFFSET,
-		    &entry, sizeof(entry));
-	entry = (iommu_virt_to_phys(iommu->ga_log_tail) &
-		 (BIT_ULL(52)-1)) & ~7ULL;
-	memcpy_toio(iommu->mmio_base + MMIO_GA_LOG_TAIL_OFFSET,
-		    &entry, sizeof(entry));
-	writel(0x00, iommu->mmio_base + MMIO_GA_HEAD_OFFSET);
-	writel(0x00, iommu->mmio_base + MMIO_GA_TAIL_OFFSET);
-
 	return 0;
 err_out:
 	free_ga_log(iommu);
-- 
2.26.3