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

Signed-off-by: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>
---
 drivers/iommu/amd/amd_iommu.h       |  1 +
 drivers/iommu/amd/amd_iommu_types.h |  1 +
 drivers/iommu/amd/iommu.c           | 22 ++++++++++++++++++++++
 drivers/iommu/amd/iommufd.c         |  3 +++
 4 files changed, 27 insertions(+)

diff --git a/drivers/iommu/amd/amd_iommu.h b/drivers/iommu/amd/amd_iommu.h
index 470e5d98c52b..f1fafa21777d 100644
--- a/drivers/iommu/amd/amd_iommu.h
+++ b/drivers/iommu/amd/amd_iommu.h
@@ -11,6 +11,7 @@
 
 #include "amd_iommu_types.h"
 
+void iommu_reset_vmmio(struct amd_iommu *iommu, u16 gid);
 irqreturn_t amd_iommu_int_thread(int irq, void *data);
 irqreturn_t amd_iommu_int_thread_evtlog(int irq, void *data);
 irqreturn_t amd_iommu_int_thread_pprlog(int irq, void *data);
diff --git a/drivers/iommu/amd/amd_iommu_types.h b/drivers/iommu/amd/amd_iommu_types.h
index f0e18a7dd7f2..53854a4f4307 100644
--- a/drivers/iommu/amd/amd_iommu_types.h
+++ b/drivers/iommu/amd/amd_iommu_types.h
@@ -221,6 +221,7 @@
 #define CMD_INV_IRT		0x05
 #define CMD_COMPLETE_PPR	0x07
 #define CMD_INV_ALL		0x08
+#define CMD_RESET_VMMIO		0x0A
 
 #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 037a50397f31..191a52b657c1 100644
--- a/drivers/iommu/amd/iommu.c
+++ b/drivers/iommu/amd/iommu.c
@@ -1429,6 +1429,18 @@ 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,
+			      bool vcmd, bool all)
+{
+	memset(cmd, 0, sizeof(*cmd));
+	cmd->data[0] = gid;
+	if (all)
+		cmd->data[0] |= (1 << 28);
+	if (vcmd)
+		cmd->data[0] |= (1 << 31);
+	CMD_SET_TYPE(cmd, CMD_RESET_VMMIO);
+}
+
 /*
  * Writes the command to the IOMMUs command buffer and informs the
  * hardware about the new command.
@@ -1663,6 +1675,16 @@ void amd_iommu_flush_all_caches(struct amd_iommu *iommu)
 	}
 }
 
+void iommu_reset_vmmio(struct amd_iommu *iommu, u16 gid)
+{
+	struct iommu_cmd cmd;
+
+	build_reset_vmmio(&cmd, gid, 1, 1);
+
+	iommu_queue_command(iommu, &cmd);
+	amd_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 5dcd3fc3ba99..06d6aa87cdcd 100644
--- a/drivers/iommu/amd/iommufd.c
+++ b/drivers/iommu/amd/iommufd.c
@@ -79,6 +79,9 @@ int amd_iommufd_viommu_init(struct iommufd_viommu *viommu, struct iommu_domain *
 	if (ret)
 		goto err_out;
 
+	/* Reset vIOMMU MMIOs to initialize the vIOMMU */
+	iommu_reset_vmmio(iommu, aviommu->gid);
+
 	ret = iommu_copy_struct_to_user(user_data, &data,
 					IOMMU_VIOMMU_TYPE_AMD,
 					reserved);
-- 
2.34.1