+ Eric, Abel
On Sat, 19 Oct 2024 at 06:55, Seshu Madhavi Puppala
<quic_spuppala@xxxxxxxxxxx> wrote:
>
>
>
> On 10/8/2024 7:30 PM, Ulf Hansson wrote:
> > On Sun, 6 Oct 2024 at 15:55, Seshu Madhavi Puppala
> > <quic_spuppala@xxxxxxxxxxx> wrote:
> >>
> >> Add mmc_host_ops hook avoid_reprogram_allkeys to control
> >> reprogramming keys to Inline Crypto Engine by vendor as some
> >> vendors might not require this feature.
> >>
> >> Signed-off-by: Seshu Madhavi Puppala <quic_spuppala@xxxxxxxxxxx>
> >> Co-developed-by: Ram Prakash Gupta <quic_rampraka@xxxxxxxxxxx>
> >> Signed-off-by: Ram Prakash Gupta <quic_rampraka@xxxxxxxxxxx>
> >> ---
> >> drivers/mmc/core/crypto.c | 8 +++++---
> >> drivers/mmc/host/sdhci.c | 6 ++++++
> >> include/linux/mmc/host.h | 7 +++++++
> >> 3 files changed, 18 insertions(+), 3 deletions(-)
> >>
> >> diff --git a/drivers/mmc/core/crypto.c b/drivers/mmc/core/crypto.c
> >> index fec4fbf16a5b..4168f7d135ff 100644
> >> --- a/drivers/mmc/core/crypto.c
> >> +++ b/drivers/mmc/core/crypto.c
> >> @@ -14,9 +14,11 @@
> >>
> >> void mmc_crypto_set_initial_state(struct mmc_host *host)
> >> {
> >> - /* Reset might clear all keys, so reprogram all the keys. */
> >> - if (host->caps2 & MMC_CAP2_CRYPTO)
> >> - blk_crypto_reprogram_all_keys(&host->crypto_profile);
> >> + if (host->ops->avoid_reprogram_allkeys && !host->ops->avoid_reprogram_allkeys()) {
> >> + /* Reset might clear all keys, so reprogram all the keys. */
> >> + if (host->caps2 & MMC_CAP2_CRYPTO)
> >> + blk_crypto_reprogram_all_keys(&host->crypto_profile);
> >
> > Don't you even need to call this once, during the first initialization
> > of the card?
>
> The first card initialization is done during the boot up for qcom socs
> and the kernel keyring contains no keys immediately after bootup.After
> the initialization of the card, the block i/o operations to encrypted
> folders will automatically trigger the corresponding program key calls
> to the crypto engine since the kernel keyring does not contain the
> required encryption key. So, it is not necessary to explicitly reprogram
> all keys for qcom socs.
Okay, I see. I have looped in Abel and Eric who worked on this
feature, just to confirm that this makes sense for them too.
I assume the reason why you want to avoid the re-programming is that
it adds latency when re-initializing the card, right? In that case, do
you have some numbers of what we save by doing this?
Kind regards
Uffe
