[v9,18/27] firmware: qcom_scm: Register Gunyah platform ops

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@quicinc.com>
Signed-off-by: Prakruthi Deepak Heragu <quic_pheragu@quicinc.com>
Signed-off-by: Elliot Berman <quic_eberman@quicinc.com>
---
 drivers/firmware/Kconfig    |   2 +
 drivers/firmware/qcom_scm.c | 100 ++++++++++++++++++++++++++++++++++++
 2 files changed, 102 insertions(+)

* Elliot Berman <quic_eberman@quicinc.com> [2023-01-20 14:46:17]:

> +	for (i = 0; i < mem_parcel->n_mem_entries; i++) {
> +		src_cpy = src;
> +		ret = qcom_scm_assign_mem(le64_to_cpu(mem_parcel->mem_entries[i].ipa_base),
> +						le64_to_cpu(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++) {
> +				vmid = le16_to_cpu(mem_parcel->acl_entries[n].vmid);
> +				if (vmid <= QCOM_SCM_MAX_MANAGED_VMID)
> +					src |= (1ull << vmid);
> +				else
> +					src |= (1ull << QCOM_SCM_RM_MANAGED_VMID);
> +			}
> +
> +			new_perms[0].vmid = QCOM_SCM_VMID_HLOS;
> +
> +			for (i--; i >= 0; i--) {
> +				src_cpy = src;
> +				ret = qcom_scm_assign_mem(
> +						le64_to_cpu(mem_parcel->mem_entries[i].ipa_base),
> +						le64_to_cpu(mem_parcel->mem_entries[i].size),
> +						&src_cpy, new_perms, 1);
> +				WARN_ON_ONCE(ret);
> +			}

We would be returning 0 incorrectly here, indicating success.

> @@ -1414,6 +1511,9 @@ 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");
> +

We should remove above registration in qcom_scm_shutdown.

On 20/01/2023 22:46, Elliot Berman wrote:
> 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@quicinc.com>
> Signed-off-by: Prakruthi Deepak Heragu <quic_pheragu@quicinc.com>
> Signed-off-by: Elliot Berman <quic_eberman@quicinc.com>
> ---
>   drivers/firmware/Kconfig    |   2 +
>   drivers/firmware/qcom_scm.c | 100 ++++++++++++++++++++++++++++++++++++
>   2 files changed, 102 insertions(+)
> 
> diff --git a/drivers/firmware/Kconfig b/drivers/firmware/Kconfig
> index b59e3041fd62..b888068ff6f2 100644
> --- a/drivers/firmware/Kconfig
> +++ b/drivers/firmware/Kconfig
> @@ -214,6 +214,8 @@ config MTK_ADSP_IPC
>   
>   config QCOM_SCM
>   	tristate
> +	select VIRT_DRIVERS
> +	select GUNYAH_PLATFORM_HOOKS

So far SCM usage has been as library of functions to talk to Secure 
world, now why is this selecting GUNYAH, it should be other way round.


>   
>   config QCOM_SCM_DOWNLOAD_MODE_DEFAULT
>   	bool "Qualcomm download mode enabled by default"
> diff --git a/drivers/firmware/qcom_scm.c b/drivers/firmware/qcom_scm.c
> index 92763dce6477..20a1434087eb 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 +1296,99 @@ 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 *rm, struct gh_rm_mem_parcel *mem_parcel)
why can't this be an exported function like other scm interfaces?

We do not need a redirection here tbh.

That will also remove the need of gunyah_platform_hooks.c altogether, 
and you could call scm functions directly.
Correct me if this is not the case.



> +{
> +	struct qcom_scm_vmperm *new_perms;
> +	u64 src, src_cpy;
> +	int ret = 0, i, n;
> +	u16 vmid;
> +
> +	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++) {
> +		vmid = le16_to_cpu(mem_parcel->acl_entries[n].vmid);
> +		if (vmid <= QCOM_SCM_MAX_MANAGED_VMID)
> +			new_perms[n].vmid = 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;
> +	}
> +
> +	src = (1ull << QCOM_SCM_VMID_HLOS);
> +
> +	for (i = 0; i < mem_parcel->n_mem_entries; i++) {
> +		src_cpy = src;
> +		ret = qcom_scm_assign_mem(le64_to_cpu(mem_parcel->mem_entries[i].ipa_base),
> +						le64_to_cpu(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++) {
> +				vmid = le16_to_cpu(mem_parcel->acl_entries[n].vmid);
> +				if (vmid <= QCOM_SCM_MAX_MANAGED_VMID)
> +					src |= (1ull << vmid);
> +				else
> +					src |= (1ull << QCOM_SCM_RM_MANAGED_VMID);
> +			}
> +
> +			new_perms[0].vmid = QCOM_SCM_VMID_HLOS;
> +
> +			for (i--; i >= 0; i--) {
> +				src_cpy = src;
> +				ret = qcom_scm_assign_mem(
> +						le64_to_cpu(mem_parcel->mem_entries[i].ipa_base),
> +						le64_to_cpu(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 *rm, struct gh_rm_mem_parcel *mem_parcel)
> +{
> +	struct qcom_scm_vmperm new_perms;
> +	u64 src = 0;
> +	int ret = 0, i, n;
> +	u16 vmid;
> +
> +	new_perms.vmid = QCOM_SCM_VMID_HLOS;
> +	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++) {
> +		vmid = le16_to_cpu(mem_parcel->acl_entries[n].vmid);
> +		if (vmid <= QCOM_SCM_MAX_MANAGED_VMID)
> +			src |= (1ull << vmid);
> +		else
> +			src |= (1ull << QCOM_SCM_RM_MANAGED_VMID);
> +	}
> +
> +	for (i = 0; i < mem_parcel->n_mem_entries; i++) {
> +		ret = qcom_scm_assign_mem(le64_to_cpu(mem_parcel->mem_entries[i].ipa_base),
> +						le64_to_cpu(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 +1511,9 @@ 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;
>   }
>