[PATCH v6 20/21] firmware: qcom_scm: Register Gunyah platform ops

[Elliot Berman]

Qualcomm platforms have a firmware entity which performs access control
to physical pages. Dynamically started Gunyah virtual machines use the
QCOM_SCM_RM_MANAGED_VMID for access. Linux thus needs to assign access
to the memory used by guest VMs. Gunyah doesn't do this operation for us
since it is the current VM (typically VMID_HLOS) delegating the access
and not Gunyah itself. Use the Gunyah platform ops to achieve this so
that only Qualcomm platforms attempt to make the needed SCM calls.

Co-developed-by: Prakruthi Deepak Heragu <quic_pheragu at quicinc.com>
Signed-off-by: Prakruthi Deepak Heragu <quic_pheragu at quicinc.com>
Signed-off-by: Elliot Berman <quic_eberman at quicinc.com>
---
 drivers/firmware/qcom_scm.c    | 114 +++++++++++++++++++++++++++++++++
 include/linux/gunyah_rsc_mgr.h |   5 ++
 2 files changed, 119 insertions(+)

diff --git a/drivers/firmware/qcom_scm.c b/drivers/firmware/qcom_scm.c
index 92763dce6477..6be7c71f8609 100644
--- a/drivers/firmware/qcom_scm.c
+++ b/drivers/firmware/qcom_scm.c
@@ -17,6 +17,7 @@
 #include <linux/clk.h>
 #include <linux/reset-controller.h>
 #include <linux/arm-smccc.h>
+#include <linux/gunyah_rsc_mgr.h>
 
 #include "qcom_scm.h"
 
@@ -27,6 +28,9 @@ module_param(download_mode, bool, 0);
 #define SCM_HAS_IFACE_CLK	BIT(1)
 #define SCM_HAS_BUS_CLK		BIT(2)
 
+#define QCOM_SCM_RM_MANAGED_VMID	0x3A
+#define QCOM_SCM_MAX_MANAGED_VMID	0x3F
+
 struct qcom_scm {
 	struct device *dev;
 	struct clk *core_clk;
@@ -1292,6 +1296,113 @@ int qcom_scm_lmh_dcvsh(u32 payload_fn, u32 payload_reg, u32 payload_val,
 }
 EXPORT_SYMBOL(qcom_scm_lmh_dcvsh);
 
+static int qcom_scm_gh_rm_pre_mem_share(struct gh_rm_mem_parcel *mem_parcel)
+{
+	struct qcom_scm_vmperm *new_perms;
+	u16 this_vmid;
+	u64 src, src_cpy;
+	int ret, i, n;
+
+	ret = gh_rm_get_vmid(&this_vmid);
+	if (ret)
+		return ret;
+
+	new_perms = kcalloc(mem_parcel->n_acl_entries, sizeof(*new_perms), GFP_KERNEL);
+	if (!new_perms)
+		return -ENOMEM;
+
+	for (n = 0; n < mem_parcel->n_acl_entries; n++) {
+		if (mem_parcel->acl_entries[n].vmid <= QCOM_SCM_MAX_MANAGED_VMID)
+			new_perms[n].vmid = mem_parcel->acl_entries[n].vmid;
+		else
+			new_perms[n].vmid = QCOM_SCM_RM_MANAGED_VMID;
+		if (mem_parcel->acl_entries[n].perms & GH_RM_ACL_X)
+			new_perms[n].perm |= QCOM_SCM_PERM_EXEC;
+		if (mem_parcel->acl_entries[n].perms & GH_RM_ACL_W)
+			new_perms[n].perm |= QCOM_SCM_PERM_WRITE;
+		if (mem_parcel->acl_entries[n].perms & GH_RM_ACL_R)
+			new_perms[n].perm |= QCOM_SCM_PERM_READ;
+	}
+
+	if (this_vmid <= QCOM_SCM_MAX_MANAGED_VMID)
+		src = (1ul << this_vmid);
+	else
+		src = (1ul << QCOM_SCM_RM_MANAGED_VMID);
+
+	for (i = 0; i < mem_parcel->n_mem_entries; i++) {
+		src_cpy = src;
+		ret = qcom_scm_assign_mem(mem_parcel->mem_entries[i].ipa_base,
+						mem_parcel->mem_entries[i].size,
+						&src_cpy, new_perms, mem_parcel->n_acl_entries);
+		if (ret) {
+			src = 0;
+			for (n = 0; n < mem_parcel->n_acl_entries; n++) {
+				if (mem_parcel->acl_entries[n].vmid <= QCOM_SCM_MAX_MANAGED_VMID)
+					src |= (1ul << mem_parcel->acl_entries[n].vmid);
+				else
+					src |= (1ul << QCOM_SCM_RM_MANAGED_VMID);
+			}
+
+			if (this_vmid <= QCOM_SCM_MAX_MANAGED_VMID)
+				new_perms[0].vmid = this_vmid;
+			else
+				new_perms[0].vmid = QCOM_SCM_RM_MANAGED_VMID;
+
+			for (i--; i >= 0; i--) {
+				src_cpy = src;
+				ret = qcom_scm_assign_mem(mem_parcel->mem_entries[i].ipa_base,
+								mem_parcel->mem_entries[i].size,
+								&src_cpy, new_perms, 1);
+				WARN_ON_ONCE(ret);
+			}
+			break;
+		}
+	}
+
+	kfree(new_perms);
+	return ret;
+}
+
+static int qcom_scm_gh_rm_post_mem_reclaim(struct gh_rm_mem_parcel *mem_parcel)
+{
+	struct qcom_scm_vmperm new_perms;
+	u16 this_vmid;
+	u64 src = 0;
+	int ret, i, n;
+
+
+	ret = gh_rm_get_vmid(&this_vmid);
+	if (ret)
+		return ret;
+
+	if (this_vmid <= QCOM_SCM_MAX_MANAGED_VMID)
+		new_perms.vmid = this_vmid;
+	else
+		new_perms.vmid = QCOM_SCM_RM_MANAGED_VMID;
+	new_perms.perm = QCOM_SCM_PERM_EXEC | QCOM_SCM_PERM_WRITE | QCOM_SCM_PERM_READ;
+
+	for (n = 0; n < mem_parcel->n_acl_entries; n++) {
+		if (mem_parcel->acl_entries[n].vmid <= QCOM_SCM_MAX_MANAGED_VMID)
+			src |= (1ul << mem_parcel->acl_entries[n].vmid);
+		else
+			src |= (1ul << QCOM_SCM_RM_MANAGED_VMID);
+	}
+
+	for (i = 0; i < mem_parcel->n_mem_entries; i++) {
+		ret = qcom_scm_assign_mem(mem_parcel->mem_entries[i].ipa_base,
+						mem_parcel->mem_entries[i].size,
+						&src, &new_perms, 1);
+		WARN_ON_ONCE(ret);
+	}
+
+	return ret;
+}
+
+static struct gunyah_rm_platform_ops qcom_scm_gh_rm_platform_ops = {
+	.pre_mem_share = qcom_scm_gh_rm_pre_mem_share,
+	.post_mem_reclaim = qcom_scm_gh_rm_post_mem_reclaim,
+};
+
 static int qcom_scm_find_dload_address(struct device *dev, u64 *addr)
 {
 	struct device_node *tcsr;
@@ -1414,6 +1525,9 @@ static int qcom_scm_probe(struct platform_device *pdev)
 	if (download_mode)
 		qcom_scm_set_download_mode(true);
 
+	if (gh_rm_register_platform_ops(&qcom_scm_gh_rm_platform_ops))
+		dev_warn(__scm->dev, "Gunyah RM platform ops were already registered\n");
+
 	return 0;
 }
 
diff --git a/include/linux/gunyah_rsc_mgr.h b/include/linux/gunyah_rsc_mgr.h
index 6e5e67e96688..710e9a045f02 100644
--- a/include/linux/gunyah_rsc_mgr.h
+++ b/include/linux/gunyah_rsc_mgr.h
@@ -142,6 +142,11 @@ void gh_rm_driver_unregister(struct gh_rm_driver *ghrm_drv);
 #define module_gh_rm_driver(ghrm_drv) \
 	module_driver(ghrm_drv, gh_rm_driver_register, gh_rm_driver_unregister)
 
+struct gunyah_rm_platform_ops {
+	int (*pre_mem_share)(struct gh_rm_mem_parcel *mem_parcel);
+	int (*post_mem_reclaim)(struct gh_rm_mem_parcel *mem_parcel);
+};
+
 #if IS_ENABLED(CONFIG_GUNYAH)
 int gh_rm_register_platform_ops(struct gunyah_rm_platform_ops *platform_ops);
 void gh_rm_unregister_platform_ops(struct gunyah_rm_platform_ops *platform_ops);
-- 
2.25.1