Re: [PATCH v1 6/8] crypto: ccp - Add vdata for platform device

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On 2/8/23 06:45, Jeremi Piotrowski wrote:
On 06/02/2023 20:13, Tom Lendacky wrote:
On 2/1/23 13:24, Jeremi Piotrowski wrote:
On Tue, Jan 31, 2023 at 02:36:01PM -0600, Tom Lendacky wrote:
On 1/23/23 09:22, Jeremi Piotrowski wrote:
When matching the "psp" platform_device, determine the register offsets
at runtime from the ASP ACPI table. Pass the parsed register offsets
>from the ASPT through platdata.

To support this scenario, mark the members of 'struct sev_vdata' and
'struct psp_vdata' non-const so that the probe function can write the
values. This does not affect the other users of sev_vdata/psp_vdata as
they define the whole struct const and the pointer in struct
sp_dev_vdata stays const too.

Signed-off-by: Jeremi Piotrowski <jpiotrowski@xxxxxxxxxxxxxxxxxxx>
---
   arch/x86/kernel/psp.c            |  3 ++
   drivers/crypto/ccp/sp-dev.h      | 12 +++----
   drivers/crypto/ccp/sp-platform.c | 57 +++++++++++++++++++++++++++++++-
   3 files changed, 65 insertions(+), 7 deletions(-)

diff --git a/arch/x86/kernel/psp.c b/arch/x86/kernel/psp.c
index 24181d132bae..68511a14df63 100644
--- a/arch/x86/kernel/psp.c
+++ b/arch/x86/kernel/psp.c
@@ -199,6 +199,9 @@ static int __init psp_init_platform_device(void)
       if (err)
           return err;
       err = platform_device_add_resources(&psp_device, res, 2);
+    if (err)
+        return err;
+    err = platform_device_add_data(&psp_device, &pdata, sizeof(pdata));
       if (err)
           return err;
diff --git a/drivers/crypto/ccp/sp-dev.h b/drivers/crypto/ccp/sp-dev.h
index 20377e67f65d..aaa651364425 100644
--- a/drivers/crypto/ccp/sp-dev.h
+++ b/drivers/crypto/ccp/sp-dev.h
@@ -40,9 +40,9 @@ struct ccp_vdata {
   };
   struct sev_vdata {
-    const unsigned int cmdresp_reg;
-    const unsigned int cmdbuff_addr_lo_reg;
-    const unsigned int cmdbuff_addr_hi_reg;
+    unsigned int cmdresp_reg;
+    unsigned int cmdbuff_addr_lo_reg;
+    unsigned int cmdbuff_addr_hi_reg;
   };
   struct tee_vdata {
@@ -56,9 +56,9 @@ struct tee_vdata {
   struct psp_vdata {
       const struct sev_vdata *sev;
       const struct tee_vdata *tee;
-    const unsigned int feature_reg;
-    const unsigned int inten_reg;
-    const unsigned int intsts_reg;
+    unsigned int feature_reg;
+    unsigned int inten_reg;
+    unsigned int intsts_reg;
   };
   /* Structure to hold SP device data */
diff --git a/drivers/crypto/ccp/sp-platform.c b/drivers/crypto/ccp/sp-platform.c
index ea8926e87981..281dbf6b150c 100644
--- a/drivers/crypto/ccp/sp-platform.c
+++ b/drivers/crypto/ccp/sp-platform.c
@@ -22,6 +22,7 @@
   #include <linux/of.h>
   #include <linux/of_address.h>
   #include <linux/acpi.h>
+#include <linux/platform_data/psp.h>
   #include "ccp-dev.h"
@@ -30,11 +31,31 @@ struct sp_platform {
       unsigned int irq_count;
   };
+#ifdef CONFIG_CRYPTO_DEV_SP_PSP
+static struct sev_vdata sev_platform = {
+    .cmdresp_reg = -1,
+    .cmdbuff_addr_lo_reg = -1,
+    .cmdbuff_addr_hi_reg = -1,
+};
+static struct psp_vdata psp_platform = {
+    .sev = &sev_platform,
+    .feature_reg = -1,
+    .inten_reg = -1,
+    .intsts_reg = -1,
+};
+#endif
+
   static const struct sp_dev_vdata dev_vdata[] = {
       {
           .bar = 0,
   #ifdef CONFIG_CRYPTO_DEV_SP_CCP
           .ccp_vdata = &ccpv3_platform,
+#endif
+    },
+    {
+        .bar = 0,
+#ifdef CONFIG_CRYPTO_DEV_SP_PSP
+        .psp_vdata = &psp_platform,
   #endif
       },
   };
@@ -57,7 +78,7 @@ MODULE_DEVICE_TABLE(of, sp_of_match);
   #endif
   static const struct platform_device_id sp_plat_match[] = {
-    { "psp" },
+    { "psp", (kernel_ulong_t)&dev_vdata[1] },
       { },
   };
   MODULE_DEVICE_TABLE(platform, sp_plat_match);
@@ -86,6 +107,38 @@ static struct sp_dev_vdata *sp_get_acpi_version(struct platform_device *pdev)
       return NULL;
   }
+static struct sp_dev_vdata *sp_get_plat_version(struct platform_device *pdev)
+{
+    struct sp_dev_vdata *drvdata = (struct sp_dev_vdata *)pdev->id_entry->driver_data;

s/drvdata/vdata/


ok

+    struct device *dev = &pdev->dev;
+

Should check for null vdata and return NULL, e.g.:

     if (!vdata)
         return NULL;


ok

+    if (drvdata == &dev_vdata[1]) {

This should be a check for vdata->psp_vdata being non-NULL and
vdata->psp_vdata->sev being non-NULL, e.g.:

     if (vdata->psp_vdata && vdata->psp_vdata->sev) {

+        struct psp_platform_data *pdata = dev_get_platdata(dev);
+
+        if (!pdata) {
+            dev_err(dev, "missing platform data\n");
+            return NULL;
+        }
+#ifdef CONFIG_CRYPTO_DEV_SP_PSP

No need for this with the above checks

+        psp_platform.feature_reg = pdata->feature_reg;

These should then be:

         vdata->psp_vdata->inten_reg = pdata->feature_reg;
         ...

I see where you're going with this and the above suggestions, but
the psp_vdata pointer is const in struct sp_dev_vdata and so is the
sev pointer in struct psp_vdata. I find these consts to be important
and doing it this way would require casting away the const. I don't
think that's worth doing.

Ok, then maybe it would be better to kmalloc a vdata structure that you fill in and then assign that to dev_vdata field for use. That could eliminate the removal of the "const" notations in one of the previous patches. I just don't think you should be changing the underlying module data that isn't expected to be changed.


I can do that and undo the removal of consts from the
struct (sev|psp)_vdata members, but the outcome would look something
like this:

static void sp_platform_fill_vdata(struct sp_dev_vdata *vdata,
					struct psp_vdata *psp,
					struct sev_vdata *sev,
					const struct psp_platform_data *pdata)
{
	struct sev_vdata sevtmp = {
		.cmdbuff_addr_hi_reg = pdata->sev_cmd_buf_hi_reg,
		.cmdbuff_addr_lo_reg = pdata->sev_cmd_buf_lo_reg,
		.cmdresp_reg = pdata->sev_cmd_resp_reg,
	};
	struct psp_vdata psptmp = {
		.feature_reg = pdata->feature_reg,
		.inten_reg = pdata->irq_en_reg,
		.intsts_reg = pdata->irq_st_reg,
		.sev = sev,
	};

	memcpy(sev, &sevtmp, sizeof(*sev));
	memcpy(psp, &psptmp, sizeof(*psp));
	vdata->psp_vdata = psp;
}

static struct sp_dev_vdata *sp_get_platform_version(struct sp_device *sp)
{
	struct sp_platform *sp_platform = sp->dev_specific;
	struct psp_platform_data *pdata;
	struct device *dev = sp->dev;
	struct sp_dev_vdata *vdata;
	struct psp_vdata *psp;
	struct sev_vdata *sev;

	pdata = dev_get_platdata(dev);
	if (!pdata) {
		dev_err(dev, "missing platform data\n");
		return NULL;
	}

	sp_platform->is_platform_device = true;

	vdata = devm_kzalloc(dev, sizeof(*vdata) + sizeof(*psp) + sizeof(*sev), GFP_KERNEL);
	if (!vdata)
		return NULL;

	psp = (void *)vdata + sizeof(*vdata);
	sev = (void *)psp + sizeof(*psp);
	sp_platform_fill_vdata(vdata, psp, sev, pdata);

	/* elided debug print */
	...

	return vdata;
}

with the const fields in the struct it's not possible to assign in any
other way than on initialization, so I need to use the helper function,
tmp structs and memcpy.

Yeah, not the prettiest, but I prefer this over altering the static data.


Could you ack that you like this approach before I post a v2?

Yes, please go with this approach.

Thanks,
Tom




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