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

Tom Lendacky
2023-02-06T19:14:09Z

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@linux.microsoft.com>
>>> ---
>>> 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.

>
>>
>>> + psp_platform.inten_reg = pdata->irq_en_reg;
>>> + psp_platform.intsts_reg = pdata->irq_st_reg;
>>> + sev_platform.cmdresp_reg = pdata->sev_cmd_resp_reg;
>>
>> And this should be:
>>
>> vdata->psp_vdata->sev->cmdbuff_addr_lo = ...
>>
>>> + sev_platform.cmdbuff_addr_lo_reg = pdata->sev_cmd_buf_lo_reg;
>>> + sev_platform.cmdbuff_addr_hi_reg = pdata->sev_cmd_buf_hi_reg;
>>> + dev_dbg(dev, "GLBL feature:\t%x\n", pdata->feature_reg);
>>
>> s/GLBL feature/PSP feature register/
>>
>>> + dev_dbg(dev, "GLBL irq en:\t%x\n", pdata->irq_en_reg);
>>
>> s/GLBL irq en/PSP IRQ enable register/
>>
>>> + dev_dbg(dev, "GLBL irq st:\t%x\n", pdata->irq_st_reg);
>>
>> s/GLBL irq st/PSP IRQ status register/
>>
>>> + dev_dbg(dev, "SEV cmdresp:\t%x\n", pdata->sev_cmd_resp_reg);
>>
>> s/SEV cmdresp/SEV cmdresp register/
>>
>>> + dev_dbg(dev, "SEV cmdbuf lo:\t%x\n", pdata->sev_cmd_buf_lo_reg);
>>
>> s/SEV cmdbuf lo/SEV cmdbuf lo register/
>>
>>> + dev_dbg(dev, "SEV cmdbuf hi:\t%x\n", pdata->sev_cmd_buf_hi_reg);
>>
>> s/SEV cmdbuf hi/SEV cmdbuf hi register/
>>
>>> + dev_dbg(dev, "SEV mbox:\t%x\n", pdata->mbox_irq_id);
>>
>> s/SEV mbox/SEV cmdresp IRQ/
>>
>
> ok to all the above rewordings
>
>>
>>> + dev_dbg(dev, "ACPI cmdresp:\t%x\n", pdata->acpi_cmd_resp_reg);
>>
>> Duplicate entry
>
> I don't see it. This is the ACPI register (the one used for the IRQ config).
> Here's how these prints look when the module is loaded with dyndbg=+p:

My bad, misread it as SEV cmdresp.

Thanks,
Tom

>
> ccp psp: GLBL feature: 0
> ccp psp: GLBL irq en: 4
> ccp psp: GLBL irq st: 8
> ccp psp: SEV cmdresp: 10
> ccp psp: SEV cmdbuf lo: 14
> ccp psp: SEV cmdbuf hi: 18
> ccp psp: SEV mbox: 1
> ccp psp: ACPI cmdresp: 20
>
>>
>>> +#endif
>>> + }
>>> + return drvdata;
>>> +}
>>> +
>>> static int sp_get_irqs(struct sp_device *sp)
>>> {
>>> struct sp_platform *sp_platform = sp->dev_specific;
>>> @@ -137,6 +190,8 @@ static int sp_platform_probe(struct platform_device *pdev)
>>> sp->dev_specific = sp_platform;
>>> sp->dev_vdata = pdev->dev.of_node ? sp_get_of_version(pdev)
>>> : sp_get_acpi_version(pdev);
>>> + if (!sp->dev_vdata && pdev->id_entry)
>>
>> Move this pdev->id_entry check into sp_get_plat_version(), returning
>> NULL if not set.
>>
>
> ok
>
>> Thanks,
>> Tom
>>
>>> + sp->dev_vdata = sp_get_plat_version(pdev);
>>> if (!sp->dev_vdata) {
>>> ret = -ENODEV;
>>> dev_err(dev, "missing driver data\n");