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From:   Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>
To:     <linux-kernel@vger.kernel.org>, <iommu@lists.linux.dev>
CC:     <joro@8bytes.org>, <will@kernel.org>, <jsnitsel@redhat.com>,
        <vasant.hegde@amd.com>, <jon.grimm@amd.com>,
        Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>,
        Maxim Levitsky <mlevitsk@redhat.com>
Subject: [PATCH 1/2] iommu/amd: Simplify and Consolidate Virtual APIC (AVIC) Enablement
Date:   Tue, 26 Jul 2022 08:43:47 -0500
Message-ID: <20220726134348.6438-2-suravee.suthikulpanit@amd.com>
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Currently, enabling AVIC requires individually detect and enable GAM and
GALOG features on each IOMMU, which is difficult to keep track on
multi-IOMMU system, where the features needs to be enabled system-wide.

In addition, these features do not need to be enabled in early stage. 
It can be delayed until after amd_iommu_init_pci().

Therefore, consolidate logic for detecting and enabling IOMMU GAM and
GALOG features into a helper function, enable_iommus_vapic(), which uses
the check_feature_on_all_iommus() helper function to ensure system-wide
support of the features before enabling them, and postpone until after
amd_iommu_init_pci().

The new function also check and clean up feature enablement residue from
previous boot (e.g. in case of booting into kdump kernel), which triggers
a WARN_ON (shown below) introduced by the commit a8d4a37d1bb9 ("iommu/amd:
Restore GA log/tail pointer on host resume") in iommu_ga_log_enable().

[    7.731955] ------------[ cut here ]------------
[    7.736575] WARNING: CPU: 0 PID: 1 at drivers/iommu/amd/init.c:829 iommu_ga_log_enable.isra.0+0x16f/0x190
[    7.746135] Modules linked in:
[    7.749193] CPU: 0 PID: 1 Comm: swapper/0 Tainted: G        W        --------  ---  5.19.0-0.rc7.53.eln120.x86_64 #1
[    7.759706] Hardware name: Dell Inc. PowerEdge R7525/04D5GJ, BIOS 2.1.6 03/09/2021
[    7.767274] RIP: 0010:iommu_ga_log_enable.isra.0+0x16f/0x190
[    7.772931] Code: 20 20 00 00 8b 00 f6 c4 01 74 da 48 8b 44 24 08 65 48 2b 04 25 28 00 00 00 75 13 48 83 c4 10 5b 5d e9 f5 00 72 00 0f 0b eb e1 <0f> 0b eb dd e8 f8 66 42 00 48 8b 15 f1 85 53 01 e9 29 ff ff ff 48
[    7.791679] RSP: 0018:ffffc90000107d20 EFLAGS: 00010206
[    7.796905] RAX: ffffc90000780000 RBX: 0000000000000100 RCX: ffffc90000780000
[    7.804038] RDX: 0000000000000001 RSI: ffffc90000780000 RDI: ffff8880451f9800
[    7.811170] RBP: ffff8880451f9800 R08: ffffffffffffffff R09: 0000000000000000
[    7.818303] R10: 0000000000000000 R11: 0000000000000000 R12: 0008000000000000
[    7.825435] R13: ffff8880462ea900 R14: 0000000000000021 R15: 0000000000000000
[    7.832572] FS:  0000000000000000(0000) GS:ffff888054a00000(0000) knlGS:0000000000000000
[    7.840657] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[    7.846400] CR2: ffff888054dff000 CR3: 0000000053210000 CR4: 0000000000350eb0
[    7.853533] Call Trace:
[    7.855979]  <TASK>
[    7.858085]  amd_iommu_enable_interrupts+0x180/0x270
[    7.863051]  ? iommu_setup+0x271/0x271
[    7.866803]  state_next+0x197/0x2c0
[    7.870295]  ? iommu_setup+0x271/0x271
[    7.874049]  iommu_go_to_state+0x24/0x2c
[    7.877976]  amd_iommu_init+0xf/0x29
[    7.881554]  pci_iommu_init+0xe/0x36
[    7.885133]  do_one_initcall+0x44/0x200
[    7.888975]  do_initcalls+0xc8/0xe1
[    7.892466]  kernel_init_freeable+0x14c/0x199
[    7.896826]  ? rest_init+0xd0/0xd0
[    7.900231]  kernel_init+0x16/0x130
[    7.903723]  ret_from_fork+0x22/0x30
[    7.907306]  </TASK>
[    7.909497] ---[ end trace 0000000000000000 ]---

Fixes: commit a8d4a37d1bb9 ("iommu/amd: Restore GA log/tail pointer on host resume")
Reported-by: Jerry Snitselaar <jsnitsel@redhat.com>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: Maxim Levitsky <mlevitsk@redhat.com>
Cc: Will Deacon <will@kernel.org> (maintainer:IOMMU DRIVERS)
Signed-off-by: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>
---
 drivers/iommu/amd/init.c | 85 ++++++++++++++++++++++++++--------------
 1 file changed, 55 insertions(+), 30 deletions(-)

diff --git a/drivers/iommu/amd/init.c b/drivers/iommu/amd/init.c
index d86496114ca5..4cd94d716122 100644
--- a/drivers/iommu/amd/init.c
+++ b/drivers/iommu/amd/init.c
@@ -908,11 +908,6 @@ static int iommu_ga_log_enable(struct amd_iommu *iommu)
 	if (!iommu->ga_log)
 		return -EINVAL;
 
-	/* Check if already running */
-	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));
@@ -2068,10 +2063,6 @@ static int __init iommu_init_pci(struct amd_iommu *iommu)
 	if (iommu_feature(iommu, FEATURE_PPR) && alloc_ppr_log(iommu))
 		return -ENOMEM;
 
-	ret = iommu_init_ga_log(iommu);
-	if (ret)
-		return ret;
-
 	if (iommu->cap & (1UL << IOMMU_CAP_NPCACHE)) {
 		pr_info("Using strict mode due to virtualization\n");
 		iommu_set_dma_strict();
@@ -2155,8 +2146,6 @@ static void print_iommu_info(void)
 	}
 	if (irq_remapping_enabled) {
 		pr_info("Interrupt remapping enabled\n");
-		if (AMD_IOMMU_GUEST_IR_VAPIC(amd_iommu_guest_ir))
-			pr_info("Virtual APIC enabled\n");
 		if (amd_iommu_xt_mode == IRQ_REMAP_X2APIC_MODE)
 			pr_info("X2APIC enabled\n");
 	}
@@ -2446,9 +2435,6 @@ static int iommu_init_irq(struct amd_iommu *iommu)
 
 	if (iommu->ppr_log != NULL)
 		iommu_feature_enable(iommu, CONTROL_PPRINT_EN);
-
-	iommu_ga_log_enable(iommu);
-
 	return 0;
 }
 
@@ -2678,8 +2664,6 @@ static void iommu_enable_ga(struct amd_iommu *iommu)
 #ifdef CONFIG_IRQ_REMAP
 	switch (amd_iommu_guest_ir) {
 	case AMD_IOMMU_GUEST_IR_VAPIC:
-		iommu_feature_enable(iommu, CONTROL_GAM_EN);
-		fallthrough;
 	case AMD_IOMMU_GUEST_IR_LEGACY_GA:
 		iommu_feature_enable(iommu, CONTROL_GA_EN);
 		iommu->irte_ops = &irte_128_ops;
@@ -2759,19 +2743,6 @@ static void early_enable_iommus(void)
 			iommu_flush_all_caches(iommu);
 		}
 	}
-
-#ifdef CONFIG_IRQ_REMAP
-	/*
-	 * Note: We have already checked GASup from IVRS table.
-	 *       Now, we need to make sure that GAMSup is set.
-	 */
-	if (AMD_IOMMU_GUEST_IR_VAPIC(amd_iommu_guest_ir) &&
-	    !check_feature_on_all_iommus(FEATURE_GAM_VAPIC))
-		amd_iommu_guest_ir = AMD_IOMMU_GUEST_IR_LEGACY_GA;
-
-	if (AMD_IOMMU_GUEST_IR_VAPIC(amd_iommu_guest_ir))
-		amd_iommu_irq_ops.capability |= (1 << IRQ_POSTING_CAP);
-#endif
 }
 
 static void enable_iommus_v2(void)
@@ -2784,10 +2755,63 @@ static void enable_iommus_v2(void)
 	}
 }
 
+static void enable_iommus_vapic(void)
+{
+#ifdef CONFIG_IRQ_REMAP
+	u32 status, i;
+	struct amd_iommu *iommu;
+
+	for_each_iommu(iommu) {
+		/*
+		 * Disable GALog if already running. It could have been enabled
+		 * in the previous boot before kdump.
+		 */
+		status = readl(iommu->mmio_base + MMIO_STATUS_OFFSET);
+		if (!(status & MMIO_STATUS_GALOG_RUN_MASK))
+			continue;
+
+		iommu_feature_disable(iommu, CONTROL_GALOG_EN);
+		iommu_feature_disable(iommu, CONTROL_GAINT_EN);
+
+		/*
+		 * Need to set and poll check the GALOGRun bit to zero before
+		 * we can set/ modify GA Log registers safely.
+		 */
+		for (i = 0; i < LOOP_TIMEOUT; ++i) {
+			status = readl(iommu->mmio_base + MMIO_STATUS_OFFSET);
+			if (!(status & MMIO_STATUS_GALOG_RUN_MASK))
+				break;
+			udelay(10);
+		}
+
+		if (WARN_ON(i >= LOOP_TIMEOUT))
+			return;
+	}
+
+	if (AMD_IOMMU_GUEST_IR_VAPIC(amd_iommu_guest_ir) &&
+	    !check_feature_on_all_iommus(FEATURE_GAM_VAPIC)) {
+		amd_iommu_guest_ir = AMD_IOMMU_GUEST_IR_LEGACY_GA;
+		return;
+	}
+
+	/* Enabling GAM support */
+	for_each_iommu(iommu) {
+		if (iommu_init_ga_log(iommu) ||
+		    iommu_ga_log_enable(iommu))
+			return;
+
+		iommu_feature_enable(iommu, CONTROL_GAM_EN);
+	}
+
+	amd_iommu_irq_ops.capability |= (1 << IRQ_POSTING_CAP);
+	pr_info("Virtual APIC enabled\n");
+#endif
+}
+
 static void enable_iommus(void)
 {
 	early_enable_iommus();
-
+	enable_iommus_vapic();
 	enable_iommus_v2();
 }
 
@@ -3126,6 +3150,7 @@ static int __init state_next(void)
 		register_syscore_ops(&amd_iommu_syscore_ops);
 		ret = amd_iommu_init_pci();
 		init_state = ret ? IOMMU_INIT_ERROR : IOMMU_PCI_INIT;
+		enable_iommus_vapic();
 		enable_iommus_v2();
 		break;
 	case IOMMU_PCI_INIT:
-- 
2.34.1