[PATCH v5 08/24] iommu/amd: Introduce Reset vMMIO Command

[Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>]

Introduce new IOMMU commands for vIOMMU to reset
virtualized MMIO registers of a particular guest.

Always program RESET_MMIO_ALL_FLAG and RESET_MMIO_VCMD_FLAG.
Propagate iommu_completion_wait() errors to the caller.

Reviewed-by: Weinan Liu <wnliu@google.com>
Signed-off-by: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>
---
 drivers/iommu/amd/amd_iommu.h       |  1 +
 drivers/iommu/amd/amd_iommu_types.h |  3 +++
 drivers/iommu/amd/iommu.c           | 21 +++++++++++++++++++++
 drivers/iommu/amd/iommufd.c         |  5 +++++
 4 files changed, 30 insertions(+)

diff --git a/drivers/iommu/amd/amd_iommu.h b/drivers/iommu/amd/amd_iommu.h
index 51e4364e8564..8c298e090889 100644
--- a/drivers/iommu/amd/amd_iommu.h
+++ b/drivers/iommu/amd/amd_iommu.h
@@ -233,4 +233,5 @@ amd_iommu_alloc_domain_nested(struct iommufd_viommu *viommu, u32 flags,
 /* Guest ID for vIOMMU */
 int amd_iommu_gid_alloc(struct amd_iommu *iommu);
 void amd_iommu_gid_free(struct amd_iommu *iommu, int gid);
+int amd_iommu_reset_vmmio(struct amd_iommu *iommu, u16 gid);
 #endif /* AMD_IOMMU_H */
diff --git a/drivers/iommu/amd/amd_iommu_types.h b/drivers/iommu/amd/amd_iommu_types.h
index 3aaaf69a1e7d..9eb9a0c190de 100644
--- a/drivers/iommu/amd/amd_iommu_types.h
+++ b/drivers/iommu/amd/amd_iommu_types.h
@@ -209,6 +209,9 @@
 #define CMD_INV_IRT		0x05
 #define CMD_COMPLETE_PPR	0x07
 #define CMD_INV_ALL		0x08
+#define CMD_RESET_VMMIO		0x0A
+#define RESET_MMIO_ALL_FLAG	BIT(28)
+#define RESET_MMIO_VCMD_FLAG	BIT(31)
 
 #define CMD_COMPL_WAIT_STORE_MASK	0x01
 #define CMD_COMPL_WAIT_INT_MASK		0x02
diff --git a/drivers/iommu/amd/iommu.c b/drivers/iommu/amd/iommu.c
index fa9708af258e..94c59f503662 100644
--- a/drivers/iommu/amd/iommu.c
+++ b/drivers/iommu/amd/iommu.c
@@ -1517,6 +1517,13 @@ static void build_inv_irt(struct iommu_cmd *cmd, u16 devid)
 	CMD_SET_TYPE(cmd, CMD_INV_IRT);
 }
 
+static void build_reset_vmmio(struct iommu_cmd *cmd, u16 gid)
+{
+	memset(cmd, 0, sizeof(*cmd));
+	cmd->data[0] = gid | RESET_MMIO_ALL_FLAG | RESET_MMIO_VCMD_FLAG;
+	CMD_SET_TYPE(cmd, CMD_RESET_VMMIO);
+}
+
 /*
  * Writes the command to the IOMMUs command buffer and informs the
  * hardware about the new command.
@@ -1770,6 +1777,20 @@ void amd_iommu_flush_all_caches(struct amd_iommu *iommu)
 	}
 }
 
+int amd_iommu_reset_vmmio(struct amd_iommu *iommu, u16 gid)
+{
+	int ret;
+	struct iommu_cmd cmd;
+
+	build_reset_vmmio(&cmd, gid);
+
+	ret = iommu_queue_command(iommu, &cmd);
+	if (ret)
+		return ret;
+
+	return iommu_completion_wait(iommu);
+}
+
 /*
  * Command send function for flushing on-device TLB
  */
diff --git a/drivers/iommu/amd/iommufd.c b/drivers/iommu/amd/iommufd.c
index 7f358e57efde..2e34491e3cf7 100644
--- a/drivers/iommu/amd/iommufd.c
+++ b/drivers/iommu/amd/iommufd.c
@@ -92,6 +92,11 @@ int amd_iommufd_viommu_init(struct iommufd_viommu *viommu, struct iommu_domain *
 
 	data.out_vfmmio_mmap_offset = aviommu->vfmmio_mmap_offset;
 
+	/* Reset vIOMMU MMIOs to initialize the vIOMMU */
+	ret = amd_iommu_reset_vmmio(iommu, aviommu->gid);
+	if (ret)
+		goto err_init;
+
 	ret = iommu_copy_struct_to_user(user_data, &data,
 					IOMMU_VIOMMU_TYPE_AMD,
 					out_vfmmio_mmap_offset);
-- 
2.34.1