* [PATCH] coco: guest: arm64: Update ARM CCA guest driver
@ 2025-10-08 13:27 Aneesh Kumar K.V (Arm)
2025-10-09 7:13 ` Aneesh Kumar K.V
` (3 more replies)
0 siblings, 4 replies; 8+ messages in thread
From: Aneesh Kumar K.V (Arm) @ 2025-10-08 13:27 UTC (permalink / raw)
To: linux-coco, linux-arm-kernel, linux-kernel
Cc: Catalin Marinas, Will Deacon, Steven Price, Gavin Shan,
Suzuki K Poulose, Jeremy Linton, Sami Mujawar,
Aneesh Kumar K.V (Arm)
Make preparatory updates to the ARM CCA guest driver:
- Switch from using a platform device to a faux device (based on
feedback in [1])
- Rename the device from `arm-cca-dev` to `arm-rsi-dev`, so that the
host driver can register an equivalent `arm-rmi-dev`
These changes are purely structural and introduce no new functionality.
Subsequent patches will extend this driver to add guest device
assignment support.
[1] https://lore.kernel.org/all/2025073035-bulginess-rematch-b92e@gregkh
Signed-off-by: Aneesh Kumar K.V (Arm) <aneesh.kumar@kernel.org>
---
NOTE:
This patch is sent early outside the patchseries to avoid userspace from
depending on the presence of the newly introduced platform device.
The platform device was added in v6.14-rc1.
arch/arm64/include/asm/rsi.h | 2 +-
arch/arm64/kernel/rsi.c | 15 -----
drivers/virt/coco/arm-cca-guest/Makefile | 3 +
.../{arm-cca-guest.c => arm-cca.c} | 65 +++++++++++--------
4 files changed, 41 insertions(+), 44 deletions(-)
rename drivers/virt/coco/arm-cca-guest/{arm-cca-guest.c => arm-cca.c} (85%)
diff --git a/arch/arm64/include/asm/rsi.h b/arch/arm64/include/asm/rsi.h
index b42aeac05340..26ef6143562b 100644
--- a/arch/arm64/include/asm/rsi.h
+++ b/arch/arm64/include/asm/rsi.h
@@ -10,7 +10,7 @@
#include <linux/jump_label.h>
#include <asm/rsi_cmds.h>
-#define RSI_PDEV_NAME "arm-cca-dev"
+#define RSI_DEV_NAME "arm-rsi-dev"
DECLARE_STATIC_KEY_FALSE(rsi_present);
diff --git a/arch/arm64/kernel/rsi.c b/arch/arm64/kernel/rsi.c
index ce4778141ec7..569ef08750e5 100644
--- a/arch/arm64/kernel/rsi.c
+++ b/arch/arm64/kernel/rsi.c
@@ -140,18 +140,3 @@ void __init arm64_rsi_init(void)
static_branch_enable(&rsi_present);
}
-
-static struct platform_device rsi_dev = {
- .name = RSI_PDEV_NAME,
- .id = PLATFORM_DEVID_NONE
-};
-
-static int __init arm64_create_dummy_rsi_dev(void)
-{
- if (is_realm_world() &&
- platform_device_register(&rsi_dev))
- pr_err("failed to register rsi platform device\n");
- return 0;
-}
-
-arch_initcall(arm64_create_dummy_rsi_dev)
diff --git a/drivers/virt/coco/arm-cca-guest/Makefile b/drivers/virt/coco/arm-cca-guest/Makefile
index 69eeba08e98a..609462ea9438 100644
--- a/drivers/virt/coco/arm-cca-guest/Makefile
+++ b/drivers/virt/coco/arm-cca-guest/Makefile
@@ -1,2 +1,5 @@
# SPDX-License-Identifier: GPL-2.0-only
+#
obj-$(CONFIG_ARM_CCA_GUEST) += arm-cca-guest.o
+
+arm-cca-guest-$(CONFIG_TSM) += arm-cca.o
diff --git a/drivers/virt/coco/arm-cca-guest/arm-cca-guest.c b/drivers/virt/coco/arm-cca-guest/arm-cca.c
similarity index 85%
rename from drivers/virt/coco/arm-cca-guest/arm-cca-guest.c
rename to drivers/virt/coco/arm-cca-guest/arm-cca.c
index 0c9ea24a200c..89d9e7f8eb5d 100644
--- a/drivers/virt/coco/arm-cca-guest/arm-cca-guest.c
+++ b/drivers/virt/coco/arm-cca-guest/arm-cca.c
@@ -1,8 +1,9 @@
// SPDX-License-Identifier: GPL-2.0-only
/*
- * Copyright (C) 2023 ARM Ltd.
+ * Copyright (C) 2025 ARM Ltd.
*/
+#include <linux/device/faux.h>
#include <linux/arm-smccc.h>
#include <linux/cc_platform.h>
#include <linux/kernel.h>
@@ -181,52 +182,60 @@ static int arm_cca_report_new(struct tsm_report *report, void *data)
return ret;
}
-static const struct tsm_report_ops arm_cca_tsm_ops = {
+static const struct tsm_report_ops arm_cca_tsm_report_ops = {
.name = KBUILD_MODNAME,
.report_new = arm_cca_report_new,
};
-/**
- * arm_cca_guest_init - Register with the Trusted Security Module (TSM)
- * interface.
- *
- * Return:
- * * %0 - Registered successfully with the TSM interface.
- * * %-ENODEV - The execution context is not an Arm Realm.
- * * %-EBUSY - Already registered.
- */
-static int __init arm_cca_guest_init(void)
+static void unregister_cca_tsm_report(void *data)
+{
+ tsm_report_unregister(&arm_cca_tsm_report_ops);
+}
+
+static int cca_tsm_probe(struct faux_device *fdev)
{
int ret;
if (!is_realm_world())
return -ENODEV;
- ret = tsm_report_register(&arm_cca_tsm_ops, NULL);
- if (ret < 0)
+ ret = tsm_report_register(&arm_cca_tsm_report_ops, NULL);
+ if (ret < 0) {
pr_err("Error %d registering with TSM\n", ret);
+ return ret;
+ }
+
+ ret = devm_add_action_or_reset(&fdev->dev, unregister_cca_tsm_report, NULL);
+ if (ret < 0) {
+ pr_err("Error %d registering devm action\n", ret);
+ unregister_cca_tsm_report(NULL);
+ return ret;
+ }
return ret;
}
-module_init(arm_cca_guest_init);
-/**
- * arm_cca_guest_exit - unregister with the Trusted Security Module (TSM)
- * interface.
- */
-static void __exit arm_cca_guest_exit(void)
+static struct faux_device *cca_tsm;
+
+static const struct faux_device_ops cca_device_ops = {
+ .probe = cca_tsm_probe,
+};
+
+static int __init cca_tsm_init(void)
{
- tsm_report_unregister(&arm_cca_tsm_ops);
+ cca_tsm = faux_device_create(RSI_DEV_NAME, NULL, &cca_device_ops);
+ if (!cca_tsm)
+ return -ENOMEM;
+ return 0;
}
-module_exit(arm_cca_guest_exit);
+module_init(cca_tsm_init);
-/* modalias, so userspace can autoload this module when RSI is available */
-static const struct platform_device_id arm_cca_match[] __maybe_unused = {
- { RSI_PDEV_NAME, 0},
- { }
-};
+static void __exit cca_tsm_exit(void)
+{
+ faux_device_destroy(cca_tsm);
+}
+module_exit(cca_tsm_exit);
-MODULE_DEVICE_TABLE(platform, arm_cca_match);
MODULE_AUTHOR("Sami Mujawar <sami.mujawar@arm.com>");
MODULE_DESCRIPTION("Arm CCA Guest TSM Driver");
MODULE_LICENSE("GPL");
--
2.43.0
^ permalink raw reply related [flat|nested] 8+ messages in thread
* Re: [PATCH] coco: guest: arm64: Update ARM CCA guest driver
2025-10-08 13:27 [PATCH] coco: guest: arm64: Update ARM CCA guest driver Aneesh Kumar K.V (Arm)
@ 2025-10-09 7:13 ` Aneesh Kumar K.V
2025-10-09 10:35 ` Jonathan Cameron
2025-10-09 10:25 ` Jonathan Cameron
` (2 subsequent siblings)
3 siblings, 1 reply; 8+ messages in thread
From: Aneesh Kumar K.V @ 2025-10-09 7:13 UTC (permalink / raw)
To: linux-coco, linux-arm-kernel, linux-kernel
Cc: Catalin Marinas, Will Deacon, Steven Price, Gavin Shan,
Suzuki K Poulose, Jeremy Linton, Sami Mujawar
"Aneesh Kumar K.V (Arm)" <aneesh.kumar@kernel.org> writes:
> Make preparatory updates to the ARM CCA guest driver:
>
> - Switch from using a platform device to a faux device (based on
> feedback in [1])
> - Rename the device from `arm-cca-dev` to `arm-rsi-dev`, so that the
> host driver can register an equivalent `arm-rmi-dev`
>
> These changes are purely structural and introduce no new functionality.
> Subsequent patches will extend this driver to add guest device
> assignment support.
>
> [1] https://lore.kernel.org/all/2025073035-bulginess-rematch-b92e@gregkh
>
I noticed that, this will break autoloading of the driver.
> Signed-off-by: Aneesh Kumar K.V (Arm) <aneesh.kumar@kernel.org>
> ---
> NOTE:
> This patch is sent early outside the patchseries to avoid userspace from
> depending on the presence of the newly introduced platform device.
> The platform device was added in v6.14-rc1.
>
> arch/arm64/include/asm/rsi.h | 2 +-
> arch/arm64/kernel/rsi.c | 15 -----
> drivers/virt/coco/arm-cca-guest/Makefile | 3 +
> .../{arm-cca-guest.c => arm-cca.c} | 65 +++++++++++--------
> 4 files changed, 41 insertions(+), 44 deletions(-)
> rename drivers/virt/coco/arm-cca-guest/{arm-cca-guest.c => arm-cca.c} (85%)
>
> diff --git a/arch/arm64/include/asm/rsi.h b/arch/arm64/include/asm/rsi.h
> index b42aeac05340..26ef6143562b 100644
> --- a/arch/arm64/include/asm/rsi.h
> +++ b/arch/arm64/include/asm/rsi.h
> @@ -10,7 +10,7 @@
> #include <linux/jump_label.h>
> #include <asm/rsi_cmds.h>
>
> -#define RSI_PDEV_NAME "arm-cca-dev"
> +#define RSI_DEV_NAME "arm-rsi-dev"
>
> DECLARE_STATIC_KEY_FALSE(rsi_present);
>
> diff --git a/arch/arm64/kernel/rsi.c b/arch/arm64/kernel/rsi.c
> index ce4778141ec7..569ef08750e5 100644
> --- a/arch/arm64/kernel/rsi.c
> +++ b/arch/arm64/kernel/rsi.c
> @@ -140,18 +140,3 @@ void __init arm64_rsi_init(void)
>
> static_branch_enable(&rsi_present);
> }
> -
> -static struct platform_device rsi_dev = {
> - .name = RSI_PDEV_NAME,
> - .id = PLATFORM_DEVID_NONE
> -};
> -
> -static int __init arm64_create_dummy_rsi_dev(void)
> -{
> - if (is_realm_world() &&
> - platform_device_register(&rsi_dev))
> - pr_err("failed to register rsi platform device\n");
> - return 0;
> -}
> -
> -arch_initcall(arm64_create_dummy_rsi_dev)
> diff --git a/drivers/virt/coco/arm-cca-guest/Makefile b/drivers/virt/coco/arm-cca-guest/Makefile
> index 69eeba08e98a..609462ea9438 100644
> --- a/drivers/virt/coco/arm-cca-guest/Makefile
> +++ b/drivers/virt/coco/arm-cca-guest/Makefile
> @@ -1,2 +1,5 @@
> # SPDX-License-Identifier: GPL-2.0-only
> +#
> obj-$(CONFIG_ARM_CCA_GUEST) += arm-cca-guest.o
> +
> +arm-cca-guest-$(CONFIG_TSM) += arm-cca.o
> diff --git a/drivers/virt/coco/arm-cca-guest/arm-cca-guest.c b/drivers/virt/coco/arm-cca-guest/arm-cca.c
> similarity index 85%
> rename from drivers/virt/coco/arm-cca-guest/arm-cca-guest.c
> rename to drivers/virt/coco/arm-cca-guest/arm-cca.c
> index 0c9ea24a200c..89d9e7f8eb5d 100644
> --- a/drivers/virt/coco/arm-cca-guest/arm-cca-guest.c
> +++ b/drivers/virt/coco/arm-cca-guest/arm-cca.c
> @@ -1,8 +1,9 @@
> // SPDX-License-Identifier: GPL-2.0-only
> /*
> - * Copyright (C) 2023 ARM Ltd.
> + * Copyright (C) 2025 ARM Ltd.
> */
>
> +#include <linux/device/faux.h>
> #include <linux/arm-smccc.h>
> #include <linux/cc_platform.h>
> #include <linux/kernel.h>
> @@ -181,52 +182,60 @@ static int arm_cca_report_new(struct tsm_report *report, void *data)
> return ret;
> }
>
> -static const struct tsm_report_ops arm_cca_tsm_ops = {
> +static const struct tsm_report_ops arm_cca_tsm_report_ops = {
> .name = KBUILD_MODNAME,
> .report_new = arm_cca_report_new,
> };
>
> -/**
> - * arm_cca_guest_init - Register with the Trusted Security Module (TSM)
> - * interface.
> - *
> - * Return:
> - * * %0 - Registered successfully with the TSM interface.
> - * * %-ENODEV - The execution context is not an Arm Realm.
> - * * %-EBUSY - Already registered.
> - */
> -static int __init arm_cca_guest_init(void)
> +static void unregister_cca_tsm_report(void *data)
> +{
> + tsm_report_unregister(&arm_cca_tsm_report_ops);
> +}
> +
> +static int cca_tsm_probe(struct faux_device *fdev)
> {
> int ret;
>
> if (!is_realm_world())
> return -ENODEV;
>
> - ret = tsm_report_register(&arm_cca_tsm_ops, NULL);
> - if (ret < 0)
> + ret = tsm_report_register(&arm_cca_tsm_report_ops, NULL);
> + if (ret < 0) {
> pr_err("Error %d registering with TSM\n", ret);
> + return ret;
> + }
> +
> + ret = devm_add_action_or_reset(&fdev->dev, unregister_cca_tsm_report, NULL);
> + if (ret < 0) {
> + pr_err("Error %d registering devm action\n", ret);
> + unregister_cca_tsm_report(NULL);
> + return ret;
> + }
>
> return ret;
> }
> -module_init(arm_cca_guest_init);
>
> -/**
> - * arm_cca_guest_exit - unregister with the Trusted Security Module (TSM)
> - * interface.
> - */
> -static void __exit arm_cca_guest_exit(void)
> +static struct faux_device *cca_tsm;
> +
> +static const struct faux_device_ops cca_device_ops = {
> + .probe = cca_tsm_probe,
> +};
> +
> +static int __init cca_tsm_init(void)
> {
> - tsm_report_unregister(&arm_cca_tsm_ops);
> + cca_tsm = faux_device_create(RSI_DEV_NAME, NULL, &cca_device_ops);
> + if (!cca_tsm)
> + return -ENOMEM;
> + return 0;
> }
> -module_exit(arm_cca_guest_exit);
> +module_init(cca_tsm_init);
>
> -/* modalias, so userspace can autoload this module when RSI is available */
> -static const struct platform_device_id arm_cca_match[] __maybe_unused = {
> - { RSI_PDEV_NAME, 0},
> - { }
> -};
> +static void __exit cca_tsm_exit(void)
> +{
> + faux_device_destroy(cca_tsm);
> +}
> +module_exit(cca_tsm_exit);
>
> -MODULE_DEVICE_TABLE(platform, arm_cca_match);
> MODULE_AUTHOR("Sami Mujawar <sami.mujawar@arm.com>");
> MODULE_DESCRIPTION("Arm CCA Guest TSM Driver");
> MODULE_LICENSE("GPL");
> --
> 2.43.0
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH] coco: guest: arm64: Update ARM CCA guest driver
2025-10-08 13:27 [PATCH] coco: guest: arm64: Update ARM CCA guest driver Aneesh Kumar K.V (Arm)
2025-10-09 7:13 ` Aneesh Kumar K.V
@ 2025-10-09 10:25 ` Jonathan Cameron
2025-10-10 14:16 ` kernel test robot
2025-10-10 15:23 ` Jeremy Linton
3 siblings, 0 replies; 8+ messages in thread
From: Jonathan Cameron @ 2025-10-09 10:25 UTC (permalink / raw)
To: Aneesh Kumar K.V (Arm)
Cc: linux-coco, linux-arm-kernel, linux-kernel, Catalin Marinas,
Will Deacon, Steven Price, Gavin Shan, Suzuki K Poulose,
Jeremy Linton, Sami Mujawar
On Wed, 8 Oct 2025 18:57:58 +0530
"Aneesh Kumar K.V (Arm)" <aneesh.kumar@kernel.org> wrote:
> Make preparatory updates to the ARM CCA guest driver:
>
> - Switch from using a platform device to a faux device (based on
> feedback in [1])
> - Rename the device from `arm-cca-dev` to `arm-rsi-dev`, so that the
> host driver can register an equivalent `arm-rmi-dev`
>
> These changes are purely structural and introduce no new functionality.
> Subsequent patches will extend this driver to add guest device
> assignment support.
>
> [1] https://lore.kernel.org/all/2025073035-bulginess-rematch-b92e@gregkh
>
Slight preference for:
Link: https://lore.kernel.org/all/2025073035-bulginess-rematch-b92e@gregkh #1
> Signed-off-by: Aneesh Kumar K.V (Arm) <aneesh.kumar@kernel.org>
> ---
> NOTE:
> This patch is sent early outside the patchseries to avoid userspace from
> depending on the presence of the newly introduced platform device.
> The platform device was added in v6.14-rc1.
>
A few trivial things inline. With those in mind.
Reviewed-by: Jonathan Cameron <jonathan.cameron@huawei.com>
> diff --git a/drivers/virt/coco/arm-cca-guest/Makefile b/drivers/virt/coco/arm-cca-guest/Makefile
> index 69eeba08e98a..609462ea9438 100644
> --- a/drivers/virt/coco/arm-cca-guest/Makefile
> +++ b/drivers/virt/coco/arm-cca-guest/Makefile
> @@ -1,2 +1,5 @@
> # SPDX-License-Identifier: GPL-2.0-only
> +#
Unrelated change. I'd drop it.
> obj-$(CONFIG_ARM_CCA_GUEST) += arm-cca-guest.o
> +
> +arm-cca-guest-$(CONFIG_TSM) += arm-cca.o
extra space after = seems a bit odd.
> diff --git a/drivers/virt/coco/arm-cca-guest/arm-cca-guest.c b/drivers/virt/coco/arm-cca-guest/arm-cca.c
> similarity index 85%
> rename from drivers/virt/coco/arm-cca-guest/arm-cca-guest.c
> rename to drivers/virt/coco/arm-cca-guest/arm-cca.c
> index 0c9ea24a200c..89d9e7f8eb5d 100644
> --- a/drivers/virt/coco/arm-cca-guest/arm-cca-guest.c
> +++ b/drivers/virt/coco/arm-cca-guest/arm-cca.c
> @@ -1,8 +1,9 @@
> // SPDX-License-Identifier: GPL-2.0-only
> /*
> - * Copyright (C) 2023 ARM Ltd.
> + * Copyright (C) 2025 ARM Ltd.
I'd expect a date range rather than updating copyright for whole file
like this. The untouched bit will still be 2023 era code.
> */
> +static int cca_tsm_probe(struct faux_device *fdev)
> {
> int ret;
>
> if (!is_realm_world())
> return -ENODEV;
>
> - ret = tsm_report_register(&arm_cca_tsm_ops, NULL);
> - if (ret < 0)
> + ret = tsm_report_register(&arm_cca_tsm_report_ops, NULL);
> + if (ret < 0) {
> pr_err("Error %d registering with TSM\n", ret);
> + return ret;
> + }
> +
> + ret = devm_add_action_or_reset(&fdev->dev, unregister_cca_tsm_report, NULL);
> + if (ret < 0) {
> + pr_err("Error %d registering devm action\n", ret);
I believe (not checked today) that devm_add_action_or_reset() can only fail
with -ENOMEM due to an allocation failure and we generally don't print
extra error messages if that happens.
So I would drop this pr_err.
> + unregister_cca_tsm_report(NULL);
> + return ret;
> + }
>
> return ret;
> }
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH] coco: guest: arm64: Update ARM CCA guest driver
2025-10-09 7:13 ` Aneesh Kumar K.V
@ 2025-10-09 10:35 ` Jonathan Cameron
2025-10-10 2:24 ` dan.j.williams
0 siblings, 1 reply; 8+ messages in thread
From: Jonathan Cameron @ 2025-10-09 10:35 UTC (permalink / raw)
To: Aneesh Kumar K.V
Cc: linux-coco, linux-arm-kernel, linux-kernel, Catalin Marinas,
Will Deacon, Steven Price, Gavin Shan, Suzuki K Poulose,
Jeremy Linton, Sami Mujawar
On Thu, 09 Oct 2025 12:43:49 +0530
Aneesh Kumar K.V <aneesh.kumar@kernel.org> wrote:
> "Aneesh Kumar K.V (Arm)" <aneesh.kumar@kernel.org> writes:
>
> > Make preparatory updates to the ARM CCA guest driver:
> >
> > - Switch from using a platform device to a faux device (based on
> > feedback in [1])
> > - Rename the device from `arm-cca-dev` to `arm-rsi-dev`, so that the
> > host driver can register an equivalent `arm-rmi-dev`
> >
> > These changes are purely structural and introduce no new functionality.
> > Subsequent patches will extend this driver to add guest device
> > assignment support.
> >
> > [1] https://lore.kernel.org/all/2025073035-bulginess-rematch-b92e@gregkh
> >
>
> I noticed that, this will break autoloading of the driver.
Ah indeed. You'd need to arrange for the arch code to call the init()
directly (possibly arch_initcall() as before or maybe directly from
arm64_rsi_init), which makes it tricky to do in a module as there
is nothing to kick off module autoloading. You could kick that off
explicitly but that's a bit ugly.
Jonathan
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH] coco: guest: arm64: Update ARM CCA guest driver
2025-10-09 10:35 ` Jonathan Cameron
@ 2025-10-10 2:24 ` dan.j.williams
2025-10-10 11:48 ` Jeremy Linton
0 siblings, 1 reply; 8+ messages in thread
From: dan.j.williams @ 2025-10-10 2:24 UTC (permalink / raw)
To: Jonathan Cameron, Aneesh Kumar K.V
Cc: linux-coco, linux-arm-kernel, linux-kernel, Catalin Marinas,
Will Deacon, Steven Price, Gavin Shan, Suzuki K Poulose,
Jeremy Linton, Sami Mujawar
Jonathan Cameron wrote:
> On Thu, 09 Oct 2025 12:43:49 +0530
> Aneesh Kumar K.V <aneesh.kumar@kernel.org> wrote:
>
> > "Aneesh Kumar K.V (Arm)" <aneesh.kumar@kernel.org> writes:
> >
> > > Make preparatory updates to the ARM CCA guest driver:
> > >
> > > - Switch from using a platform device to a faux device (based on
> > > feedback in [1])
> > > - Rename the device from `arm-cca-dev` to `arm-rsi-dev`, so that the
> > > host driver can register an equivalent `arm-rmi-dev`
> > >
> > > These changes are purely structural and introduce no new functionality.
> > > Subsequent patches will extend this driver to add guest device
> > > assignment support.
> > >
> > > [1] https://lore.kernel.org/all/2025073035-bulginess-rematch-b92e@gregkh
> > >
> >
> > I noticed that, this will break autoloading of the driver.
>
> Ah indeed. You'd need to arrange for the arch code to call the init()
> directly (possibly arch_initcall() as before or maybe directly from
> arm64_rsi_init), which makes it tricky to do in a module as there
> is nothing to kick off module autoloading. You could kick that off
> explicitly but that's a bit ugly.
Does ARM64 not have the equivalent of MODULE_DEVICE_TABLE(x86cpu, ...)?
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH] coco: guest: arm64: Update ARM CCA guest driver
2025-10-10 2:24 ` dan.j.williams
@ 2025-10-10 11:48 ` Jeremy Linton
0 siblings, 0 replies; 8+ messages in thread
From: Jeremy Linton @ 2025-10-10 11:48 UTC (permalink / raw)
To: dan.j.williams, Jonathan Cameron, Aneesh Kumar K.V
Cc: linux-coco, linux-arm-kernel, linux-kernel, Catalin Marinas,
Will Deacon, Steven Price, Gavin Shan, Suzuki K Poulose,
Sami Mujawar
Hi,
Hi,
On 10/9/25 9:24 PM, dan.j.williams@intel.com wrote:
> Jonathan Cameron wrote:
>> On Thu, 09 Oct 2025 12:43:49 +0530
>> Aneesh Kumar K.V <aneesh.kumar@kernel.org> wrote:
>>
>>> "Aneesh Kumar K.V (Arm)" <aneesh.kumar@kernel.org> writes:
>>>
>>>> Make preparatory updates to the ARM CCA guest driver:
>>>>
>>>> - Switch from using a platform device to a faux device (based on
>>>> feedback in [1])
>>>> - Rename the device from `arm-cca-dev` to `arm-rsi-dev`, so that the
>>>> host driver can register an equivalent `arm-rmi-dev`
>>>>
>>>> These changes are purely structural and introduce no new functionality.
>>>> Subsequent patches will extend this driver to add guest device
>>>> assignment support.
>>>>
>>>> [1] https://lore.kernel.org/all/2025073035-bulginess-rematch-b92e@gregkh
>>>>
>>>
>>> I noticed that, this will break autoloading of the driver.
>>
>> Ah indeed. You'd need to arrange for the arch code to call the init()
>> directly (possibly arch_initcall() as before or maybe directly from
>> arm64_rsi_init), which makes it tricky to do in a module as there
>> is nothing to kick off module autoloading. You could kick that off
>> explicitly but that's a bit ugly.
>
> Does ARM64 not have the equivalent of MODULE_DEVICE_TABLE(x86cpu, ...)?
No, it doesn't. There is a hwcap based method, but that requires
allocating a hwcap.
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH] coco: guest: arm64: Update ARM CCA guest driver
2025-10-08 13:27 [PATCH] coco: guest: arm64: Update ARM CCA guest driver Aneesh Kumar K.V (Arm)
2025-10-09 7:13 ` Aneesh Kumar K.V
2025-10-09 10:25 ` Jonathan Cameron
@ 2025-10-10 14:16 ` kernel test robot
2025-10-10 15:23 ` Jeremy Linton
3 siblings, 0 replies; 8+ messages in thread
From: kernel test robot @ 2025-10-10 14:16 UTC (permalink / raw)
To: Aneesh Kumar K.V (Arm), linux-coco, linux-arm-kernel,
linux-kernel
Cc: llvm, oe-kbuild-all, Catalin Marinas, Will Deacon, Steven Price,
Gavin Shan, Suzuki K Poulose, Jeremy Linton, Sami Mujawar,
Aneesh Kumar K.V (Arm)
Hi Aneesh,
kernel test robot noticed the following build errors:
[auto build test ERROR on arm64/for-next/core]
[also build test ERROR on arm/for-next arm/fixes kvmarm/next soc/for-next linus/master v6.17 next-20251009]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]
url: https://github.com/intel-lab-lkp/linux/commits/Aneesh-Kumar-K-V-Arm/coco-guest-arm64-Update-ARM-CCA-guest-driver/20251009-203207
base: https://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-next/core
patch link: https://lore.kernel.org/r/20251008132758.784275-1-aneesh.kumar%40kernel.org
patch subject: [PATCH] coco: guest: arm64: Update ARM CCA guest driver
config: arm64-allmodconfig (https://download.01.org/0day-ci/archive/20251010/202510102121.hLzgHTck-lkp@intel.com/config)
compiler: clang version 19.1.7 (https://github.com/llvm/llvm-project cd708029e0b2869e80abe31ddb175f7c35361f90)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20251010/202510102121.hLzgHTck-lkp@intel.com/reproduce)
If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202510102121.hLzgHTck-lkp@intel.com/
All errors (new ones prefixed by >>):
>> ld.lld: error: cannot open drivers/virt/coco/arm-cca-guest/: Is a directory
--
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH] coco: guest: arm64: Update ARM CCA guest driver
2025-10-08 13:27 [PATCH] coco: guest: arm64: Update ARM CCA guest driver Aneesh Kumar K.V (Arm)
` (2 preceding siblings ...)
2025-10-10 14:16 ` kernel test robot
@ 2025-10-10 15:23 ` Jeremy Linton
3 siblings, 0 replies; 8+ messages in thread
From: Jeremy Linton @ 2025-10-10 15:23 UTC (permalink / raw)
To: Aneesh Kumar K.V (Arm), linux-coco, linux-arm-kernel,
linux-kernel
Cc: Catalin Marinas, Will Deacon, Steven Price, Gavin Shan,
Suzuki K Poulose, Sami Mujawar
On 10/8/25 8:27 AM, Aneesh Kumar K.V (Arm) wrote:
> Make preparatory updates to the ARM CCA guest driver:
>
> - Switch from using a platform device to a faux device (based on
> feedback in [1])
> - Rename the device from `arm-cca-dev` to `arm-rsi-dev`, so that the
> host driver can register an equivalent `arm-rmi-dev`
>
> These changes are purely structural and introduce no new functionality.
> Subsequent patches will extend this driver to add guest device
> assignment support.
>
> [1] https://lore.kernel.org/all/2025073035-bulginess-rematch-b92e@gregkh
>
> Signed-off-by: Aneesh Kumar K.V (Arm) <aneesh.kumar@kernel.org>
> ---
> NOTE:
> This patch is sent early outside the patchseries to avoid userspace from
> depending on the presence of the newly introduced platform device.
> The platform device was added in v6.14-rc1.
At this point, changing the platform device name also breaks systemd's
confidential vm detection, because its using this device name as the
first step.
>
> arch/arm64/include/asm/rsi.h | 2 +-
> arch/arm64/kernel/rsi.c | 15 -----
> drivers/virt/coco/arm-cca-guest/Makefile | 3 +
> .../{arm-cca-guest.c => arm-cca.c} | 65 +++++++++++--------
> 4 files changed, 41 insertions(+), 44 deletions(-)
> rename drivers/virt/coco/arm-cca-guest/{arm-cca-guest.c => arm-cca.c} (85%)
>
> diff --git a/arch/arm64/include/asm/rsi.h b/arch/arm64/include/asm/rsi.h
> index b42aeac05340..26ef6143562b 100644
> --- a/arch/arm64/include/asm/rsi.h
> +++ b/arch/arm64/include/asm/rsi.h
> @@ -10,7 +10,7 @@
> #include <linux/jump_label.h>
> #include <asm/rsi_cmds.h>
>
> -#define RSI_PDEV_NAME "arm-cca-dev"
> +#define RSI_DEV_NAME "arm-rsi-dev"
>
> DECLARE_STATIC_KEY_FALSE(rsi_present);
>
> diff --git a/arch/arm64/kernel/rsi.c b/arch/arm64/kernel/rsi.c
> index ce4778141ec7..569ef08750e5 100644
> --- a/arch/arm64/kernel/rsi.c
> +++ b/arch/arm64/kernel/rsi.c
> @@ -140,18 +140,3 @@ void __init arm64_rsi_init(void)
>
> static_branch_enable(&rsi_present);
> }
> -
> -static struct platform_device rsi_dev = {
> - .name = RSI_PDEV_NAME,
> - .id = PLATFORM_DEVID_NONE
> -};
> -
> -static int __init arm64_create_dummy_rsi_dev(void)
> -{
> - if (is_realm_world() &&
> - platform_device_register(&rsi_dev))
> - pr_err("failed to register rsi platform device\n");
> - return 0;
> -}
> -
> -arch_initcall(arm64_create_dummy_rsi_dev)
> diff --git a/drivers/virt/coco/arm-cca-guest/Makefile b/drivers/virt/coco/arm-cca-guest/Makefile
> index 69eeba08e98a..609462ea9438 100644
> --- a/drivers/virt/coco/arm-cca-guest/Makefile
> +++ b/drivers/virt/coco/arm-cca-guest/Makefile
> @@ -1,2 +1,5 @@
> # SPDX-License-Identifier: GPL-2.0-only
> +#
> obj-$(CONFIG_ARM_CCA_GUEST) += arm-cca-guest.o
> +
> +arm-cca-guest-$(CONFIG_TSM) += arm-cca.o
> diff --git a/drivers/virt/coco/arm-cca-guest/arm-cca-guest.c b/drivers/virt/coco/arm-cca-guest/arm-cca.c
> similarity index 85%
> rename from drivers/virt/coco/arm-cca-guest/arm-cca-guest.c
> rename to drivers/virt/coco/arm-cca-guest/arm-cca.c
> index 0c9ea24a200c..89d9e7f8eb5d 100644
> --- a/drivers/virt/coco/arm-cca-guest/arm-cca-guest.c
> +++ b/drivers/virt/coco/arm-cca-guest/arm-cca.c
> @@ -1,8 +1,9 @@
> // SPDX-License-Identifier: GPL-2.0-only
> /*
> - * Copyright (C) 2023 ARM Ltd.
> + * Copyright (C) 2025 ARM Ltd.
> */
>
> +#include <linux/device/faux.h>
> #include <linux/arm-smccc.h>
> #include <linux/cc_platform.h>
> #include <linux/kernel.h>
> @@ -181,52 +182,60 @@ static int arm_cca_report_new(struct tsm_report *report, void *data)
> return ret;
> }
>
> -static const struct tsm_report_ops arm_cca_tsm_ops = {
> +static const struct tsm_report_ops arm_cca_tsm_report_ops = {
> .name = KBUILD_MODNAME,
> .report_new = arm_cca_report_new,
> };
>
> -/**
> - * arm_cca_guest_init - Register with the Trusted Security Module (TSM)
> - * interface.
> - *
> - * Return:
> - * * %0 - Registered successfully with the TSM interface.
> - * * %-ENODEV - The execution context is not an Arm Realm.
> - * * %-EBUSY - Already registered.
> - */
> -static int __init arm_cca_guest_init(void)
> +static void unregister_cca_tsm_report(void *data)
> +{
> + tsm_report_unregister(&arm_cca_tsm_report_ops);
> +}
> +
> +static int cca_tsm_probe(struct faux_device *fdev)
> {
> int ret;
>
> if (!is_realm_world())
> return -ENODEV;
>
> - ret = tsm_report_register(&arm_cca_tsm_ops, NULL);
> - if (ret < 0)
> + ret = tsm_report_register(&arm_cca_tsm_report_ops, NULL);
> + if (ret < 0) {
> pr_err("Error %d registering with TSM\n", ret);
> + return ret;
> + }
> +
> + ret = devm_add_action_or_reset(&fdev->dev, unregister_cca_tsm_report, NULL);
> + if (ret < 0) {
> + pr_err("Error %d registering devm action\n", ret);
> + unregister_cca_tsm_report(NULL);
> + return ret;
> + }
>
> return ret;
> }
> -module_init(arm_cca_guest_init);
>
> -/**
> - * arm_cca_guest_exit - unregister with the Trusted Security Module (TSM)
> - * interface.
> - */
> -static void __exit arm_cca_guest_exit(void)
> +static struct faux_device *cca_tsm;
> +
> +static const struct faux_device_ops cca_device_ops = {
> + .probe = cca_tsm_probe,
> +};
> +
> +static int __init cca_tsm_init(void)
> {
> - tsm_report_unregister(&arm_cca_tsm_ops);
> + cca_tsm = faux_device_create(RSI_DEV_NAME, NULL, &cca_device_ops);
> + if (!cca_tsm)
> + return -ENOMEM;
> + return 0;
> }
> -module_exit(arm_cca_guest_exit);
> +module_init(cca_tsm_init);
>
> -/* modalias, so userspace can autoload this module when RSI is available */
> -static const struct platform_device_id arm_cca_match[] __maybe_unused = {
> - { RSI_PDEV_NAME, 0},
> - { }
> -};
> +static void __exit cca_tsm_exit(void)
> +{
> + faux_device_destroy(cca_tsm);
> +}
> +module_exit(cca_tsm_exit);
>
> -MODULE_DEVICE_TABLE(platform, arm_cca_match);
> MODULE_AUTHOR("Sami Mujawar <sami.mujawar@arm.com>");
> MODULE_DESCRIPTION("Arm CCA Guest TSM Driver");
> MODULE_LICENSE("GPL");
^ permalink raw reply [flat|nested] 8+ messages in thread
end of thread, other threads:[~2025-10-10 15:23 UTC | newest]
Thread overview: 8+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2025-10-08 13:27 [PATCH] coco: guest: arm64: Update ARM CCA guest driver Aneesh Kumar K.V (Arm)
2025-10-09 7:13 ` Aneesh Kumar K.V
2025-10-09 10:35 ` Jonathan Cameron
2025-10-10 2:24 ` dan.j.williams
2025-10-10 11:48 ` Jeremy Linton
2025-10-09 10:25 ` Jonathan Cameron
2025-10-10 14:16 ` kernel test robot
2025-10-10 15:23 ` Jeremy Linton
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