On Thu, Aug 04, 2022 at 08:13:35AM -0500, Tom Lendacky wrote:
> On 8/3/22 20:02, Jarkko Sakkinen wrote:
> > From: Jarkko Sakkinen <[email protected]>
> >
> > SEV-SNP does not initialize to a legit state, unless the firmware is
> > loaded twice, when SEP API version < 1.43, and the firmware is updated
> > to a later version. Because of this user space needs to work around
> > this with "rmmod && modprobe" combo. Fix this by implementing the
> > workaround to the driver.
>
> The SNP hypervisor patches are placing a minimum supported version
> requirement for the SEV firmware that exceeds the specified version
> above [1] (for the reason above, as well as some others), so this patch
> is not needed, NAK.
>
> [1] https://lore.kernel.org/lkml/87a0481526e66ddd5f6192cbb43a50708aee2883.1655761627.git.ashish.kalra@amd.com/
>
> Thanks,
> Tom
Hi Tom,
Is there any particular reason for this restriction? Does SNP not work with API
version <v1.51? Do you have a link to a changelog that describes the changes
between different firmware versions?
Thanks,
Jeremi
>
> >
> > Reported-by: Harald Hoyer <[email protected]>
> > Signed-off-by: Jarkko Sakkinen <[email protected]>
> > ---
> > drivers/crypto/ccp/sev-dev.c | 22 +++++++++++++++++++---
> > 1 file changed, 19 insertions(+), 3 deletions(-)
> >
> > diff --git a/drivers/crypto/ccp/sev-dev.c b/drivers/crypto/ccp/sev-dev.c
> > index 799b476fc3e8..f2abb7439dde 100644
> > --- a/drivers/crypto/ccp/sev-dev.c
> > +++ b/drivers/crypto/ccp/sev-dev.c
> > @@ -76,6 +76,9 @@ static void *sev_es_tmr;
> > #define NV_LENGTH (32 * 1024)
> > static void *sev_init_ex_buffer;
> > +/*
> > + * SEV API version >= maj.min?
> > + */
> > static inline bool sev_version_greater_or_equal(u8 maj, u8 min)
> > {
> > struct sev_device *sev = psp_master->sev_data;
> > @@ -89,6 +92,14 @@ static inline bool sev_version_greater_or_equal(u8 maj, u8 min)
> > return false;
> > }
> > +/*
> > + * SEV API version < maj.min?
> > + */
> > +static inline bool sev_version_less(u8 maj, u8 min)
> > +{
> > + return !sev_version_greater_or_equal(maj, min);
> > +}
> > +
> > static void sev_irq_handler(int irq, void *data, unsigned int status)
> > {
> > struct sev_device *sev = data;
> > @@ -1274,6 +1285,7 @@ void sev_pci_init(void)
> > {
> > struct sev_device *sev = psp_master->sev_data;
> > int error, rc;
> > + int i;
> > if (!sev)
> > return;
> > @@ -1283,9 +1295,13 @@ void sev_pci_init(void)
> > if (sev_get_api_version())
> > goto err;
> > - if (sev_version_greater_or_equal(0, 15) &&
> > - sev_update_firmware(sev->dev) == 0)
> > - sev_get_api_version();
> > + /*
> > + * SEV-SNP does not work properly before loading the FW twice in the API
> > + * versions older than SEV 1.43.
> > + */
> > + for (i = 0; i < sev_version_greater_or_equal(0, 15) + sev_version_less(1, 43); i++)
> > + if (sev_update_firmware(sev->dev) == 0)
> > + sev_get_api_version();
> > /* If an init_ex_path is provided rely on INIT_EX for PSP initialization
> > * instead of INIT.