[PATCH v7 4/4] x86/sev: register tpm-svsm platform device

[Stefano Garzarella]

From: Stefano Garzarella <sgarz...@redhat.com>

SNP platform can provide a vTPM device emulated by SVSM.

The "tpm-svsm" device can be handled by the platform driver added
by the previous commit in drivers/char/tpm/tpm_svsm.c

Register the platform device only when SVSM is available and it
supports vTPM commands as checked by snp_svsm_vtpm_probe().

Reviewed-by: Tom Lendacky <thomas.lenda...@amd.com>
Reviewed-by: Jarkko Sakkinen <jar...@kernel.org>
Signed-off-by: Stefano Garzarella <sgarz...@redhat.com>
---
v7:
- added Jarkko's R-b
- call snp_svsm_vtpm_probe() before registering the device [Borislav]
- s/device/devices in pr_info [Tom]
- updated commit description
v6:
- added Tom's R-b
v4:
- explained better why we register it anyway in the commit message
---
 arch/x86/coco/sev/core.c | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/arch/x86/coco/sev/core.c b/arch/x86/coco/sev/core.c
index 3bc5b47e7304..54272c9777cf 100644
--- a/arch/x86/coco/sev/core.c
+++ b/arch/x86/coco/sev/core.c
@@ -2688,6 +2688,11 @@ static struct platform_device sev_guest_device = {
        .id             = -1,
 };
 
+static struct platform_device tpm_svsm_device = {
+       .name           = "tpm-svsm",
+       .id             = -1,
+};
+
 static int __init snp_init_platform_device(void)
 {
        if (!cc_platform_has(CC_ATTR_GUEST_SEV_SNP))
@@ -2696,7 +2701,11 @@ static int __init snp_init_platform_device(void)
        if (platform_device_register(&sev_guest_device))
                return -ENODEV;
 
-       pr_info("SNP guest platform device initialized.\n");
+       if (snp_svsm_vtpm_probe() &&
+           platform_device_register(&tpm_svsm_device))
+               return -ENODEV;
+
+       pr_info("SNP guest platform devices initialized.\n");
        return 0;
 }
 device_initcall(snp_init_platform_device);
-- 
2.49.0