[PATCH 3/4] crypto/ccp: support setting RAPL_DIS in SNP_INIT_EX

[Tycho Andersen <tycho@kernel.org>]

From: "Tycho Andersen (AMD)" <tycho@kernel.org>

The kernel allows setting the RAPL_DIS policy bit, but had no way to set
the RAPL_DIS bit during SNP_INIT_EX. Setting the policy bit would always
result in:

    [  898.840286] ccp 0000:a9:00.5: sev command 0xa0 failed (0x00000007)

Allow setting the RAPL_DIS bit during SNP_INIT_EX via a module parameter.
If the hardware does not support RAPL_DIS, log and disable the module
parameter.

Signed-off-by: Tycho Andersen (AMD) <tycho@kernel.org>
---
 drivers/crypto/ccp/sev-dev.c | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/drivers/crypto/ccp/sev-dev.c b/drivers/crypto/ccp/sev-dev.c
index 096f993974d1..362126453ef0 100644
--- a/drivers/crypto/ccp/sev-dev.c
+++ b/drivers/crypto/ccp/sev-dev.c
@@ -75,6 +75,10 @@ static bool psp_init_on_probe = true;
 module_param(psp_init_on_probe, bool, 0444);
 MODULE_PARM_DESC(psp_init_on_probe, "  if true, the PSP will be initialized on module init. Else the PSP will be initialized on the first command requiring it");
 
+static bool rapl_disable;
+module_param(rapl_disable, bool, 0444);
+MODULE_PARM_DESC(rapl_disable, "  if true, the RAPL_DIS bit will be set during INIT_EX if supported");
+
 #if IS_ENABLED(CONFIG_PCI_TSM)
 static bool sev_tio_enabled = true;
 module_param_named(tio, sev_tio_enabled, bool, 0444);
@@ -1428,6 +1432,16 @@ static int __sev_snp_init_locked(int *error, unsigned int max_snp_asid)
 			data.max_snp_asid = max_snp_asid;
 		}
 
+		if (rapl_disable) {
+			if (sev->snp_feat_info_0.ecx & SNP_RAPL_DISABLE_SUPPORTED) {
+				data.rapl_dis = 1;
+			} else {
+				dev_info(sev->dev,
+					"SEV: RAPL_DIS requested, but not supported");
+				rapl_disable = false;
+			}
+		}
+
 		data.init_rmp = 1;
 		data.list_paddr_en = 1;
 		data.list_paddr = __psp_pa(snp_range_list);
-- 
2.53.0