linux-kernel - [PATCH 5/9] iommu/amd: Convert Event Log pointer to use struct amd_iommu

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Date: Tue, 30 Apr 2024 15:24:26 +0000
From: Suravee Suthikulpanit <suravee.suthikulpanit@....com>
To: <linux-kernel@...r.kernel.org>, <iommu@...ts.linux.dev>, <joro@...tes.org>
CC: <thomas.lendacky@....com>, <vasant.hegde@....com>, <michael.roth@....com>,
	<jon.grimm@....com>, <rientjes@...gle.com>, Suravee Suthikulpanit
	<suravee.suthikulpanit@....com>
Subject: [PATCH 5/9] iommu/amd: Convert Event Log pointer to use struct amd_iommu_mem

And specify the memory to be 4K-aligned when running in SNP host, and
to be decrypted when running in an SEV guest so that the VMM can access
the memory successfully.

Signed-off-by: Suravee Suthikulpanit <suravee.suthikulpanit@....com>
---
 drivers/iommu/amd/amd_iommu_types.h |  2 +-
 drivers/iommu/amd/init.c            | 20 +++++++++++++-------
 drivers/iommu/amd/iommu.c           |  2 +-
 3 files changed, 15 insertions(+), 9 deletions(-)

diff --git a/drivers/iommu/amd/amd_iommu_types.h b/drivers/iommu/amd/amd_iommu_types.h
index e671e9220a21..af4e9ca6414e 100644
--- a/drivers/iommu/amd/amd_iommu_types.h
+++ b/drivers/iommu/amd/amd_iommu_types.h
@@ -738,7 +738,7 @@ struct amd_iommu {
 	u32 cmd_buf_tail;
 
 	/* event buffer virtual address */
-	u8 *evt_buf;
+	struct amd_iommu_mem evt_buf_mem;
 
 	/* Name for event log interrupt */
 	unsigned char evt_irq_name[16];
diff --git a/drivers/iommu/amd/init.c b/drivers/iommu/amd/init.c
index 51861874656e..5242a9a16946 100644
--- a/drivers/iommu/amd/init.c
+++ b/drivers/iommu/amd/init.c
@@ -860,19 +860,25 @@ void *__init iommu_alloc_4k_pages(struct amd_iommu *iommu, gfp_t gfp,
 /* allocates the memory where the IOMMU will log its events to */
 static int __init alloc_event_buffer(struct amd_iommu *iommu)
 {
-	iommu->evt_buf = iommu_alloc_4k_pages(iommu, GFP_KERNEL,
-					      EVT_BUFFER_SIZE);
+	struct amd_iommu_mem *mem = &iommu->evt_buf_mem;
 
-	return iommu->evt_buf ? 0 : -ENOMEM;
+	mem->modes = ALLOC_MODE_4K | ALLOC_MODE_GUEST_MEM_DECRYPT;
+	mem->order = get_order(EVT_BUFFER_SIZE);
+	mem->buf = amd_iommu_get_zeroed_mem(GFP_KERNEL, mem);
+	if (!mem->buf)
+		return -ENOMEM;
+
+	return 0;
 }
 
 static void iommu_enable_event_buffer(struct amd_iommu *iommu)
 {
 	u64 entry;
 
-	BUG_ON(iommu->evt_buf == NULL);
+	BUG_ON(iommu->evt_buf_mem.buf == NULL);
 
-	entry = iommu_virt_to_phys(iommu->evt_buf) | EVT_LEN_MASK;
+	entry = amd_iommu_mem_to_phys(&iommu->evt_buf_mem);
+	entry |= EVT_LEN_MASK;
 
 	memcpy_toio(iommu->mmio_base + MMIO_EVT_BUF_OFFSET,
 		    &entry, sizeof(entry));
@@ -894,7 +900,7 @@ static void iommu_disable_event_buffer(struct amd_iommu *iommu)
 
 static void __init free_event_buffer(struct amd_iommu *iommu)
 {
-	iommu_free_pages(iommu->evt_buf, get_order(EVT_BUFFER_SIZE));
+	amd_iommu_free_mem(&iommu->evt_buf_mem);
 }
 
 static void free_ga_log(struct amd_iommu *iommu)
@@ -3838,7 +3844,7 @@ int amd_iommu_snp_disable(void)
 		return 0;
 
 	for_each_iommu(iommu) {
-		ret = iommu_make_shared(iommu->evt_buf, EVT_BUFFER_SIZE);
+		ret = iommu_make_shared(iommu->evt_buf_mem.buf, EVT_BUFFER_SIZE);
 		if (ret)
 			return ret;
 
diff --git a/drivers/iommu/amd/iommu.c b/drivers/iommu/amd/iommu.c
index bd29d26c8d44..4f95c726e139 100644
--- a/drivers/iommu/amd/iommu.c
+++ b/drivers/iommu/amd/iommu.c
@@ -890,7 +890,7 @@ static void iommu_poll_events(struct amd_iommu *iommu)
 	tail = readl(iommu->mmio_base + MMIO_EVT_TAIL_OFFSET);
 
 	while (head != tail) {
-		iommu_print_event(iommu, iommu->evt_buf + head);
+		iommu_print_event(iommu, (u8 *)iommu->evt_buf_mem.buf + head);
 		head = (head + EVENT_ENTRY_SIZE) % EVT_BUFFER_SIZE;
 	}
 
-- 
2.34.1