On Tue, Nov 9, 2021 at 10:31 AM Sean Christopherson <seanjc@xxxxxxxxxx> wrote: > > On Tue, Nov 09, 2021, Peter Gonda wrote: > > On Tue, Nov 9, 2021 at 9:31 AM Sean Christopherson <seanjc@xxxxxxxxxx> wrote: > > > > > > On Tue, Nov 02, 2021, Peter Gonda wrote: > > > > This change moves the data corrupted retry of SEV_INIT into the > > > > > > Use imperative mood. > > > > Will do for next revision > > > > > > > > > __sev_platform_init_locked() function. This is for upcoming INIT_EX > > > > support as well as helping direct callers of > > > > __sev_platform_init_locked() which currently do not support the > > > > retry. > > > > > > > > Signed-off-by: Peter Gonda <pgonda@xxxxxxxxxx> > > > > Reviewed-by: Marc Orr <marcorr@xxxxxxxxxx> > > > > Acked-by: David Rientjes <rientjes@xxxxxxxxxx> > > > > Acked-by: Tom Lendacky <thomas.lendacky@xxxxxxx> > > > > Cc: Tom Lendacky <thomas.lendacky@xxxxxxx> > > > > Cc: Brijesh Singh <brijesh.singh@xxxxxxx> > > > > Cc: Marc Orr <marcorr@xxxxxxxxxx> > > > > Cc: Joerg Roedel <jroedel@xxxxxxx> > > > > Cc: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx> > > > > Cc: David Rientjes <rientjes@xxxxxxxxxx> > > > > Cc: John Allen <john.allen@xxxxxxx> > > > > Cc: "David S. Miller" <davem@xxxxxxxxxxxxx> > > > > Cc: Paolo Bonzini <pbonzini@xxxxxxxxxx> > > > > Cc: linux-crypto@xxxxxxxxxxxxxxx > > > > Cc: linux-kernel@xxxxxxxxxxxxxxx > > > > --- > > > > drivers/crypto/ccp/sev-dev.c | 24 ++++++++++++------------ > > > > 1 file changed, 12 insertions(+), 12 deletions(-) > > > > > > > > diff --git a/drivers/crypto/ccp/sev-dev.c b/drivers/crypto/ccp/sev-dev.c > > > > index ec89a82ba267..e4bc833949a0 100644 > > > > --- a/drivers/crypto/ccp/sev-dev.c > > > > +++ b/drivers/crypto/ccp/sev-dev.c > > > > @@ -267,6 +267,18 @@ static int __sev_platform_init_locked(int *error) > > > > } > > > > > > > > rc = __sev_do_cmd_locked(SEV_CMD_INIT, &data, error); > > > > + if (rc && *error == SEV_RET_SECURE_DATA_INVALID) { > > > > > > There are no guarantees that @error is non-NULL as this is reachable via an > > > exported function, sev_platform_init(). Which ties in with my complaints in the > > > previous patch that the API is a bit of a mess. > > > > That seems like a bug from the caller right? Is it typical that we > > sanity-check the caller in these instances? > > sev-dev.c needs to make up its mind. __sev_do_cmd_locked() very clearly allows > a NULL @error, ergo all of the wrappers for sev_do_cmd() support a NULL @error. > > > For example the same comment could be made here: > > https://elixir.bootlin.com/linux/latest/source/drivers/crypto/ccp/sev-dev.c#L336 > > > > ``` > > static int sev_get_platform_state(int *state, int *error) > > { > > struct sev_user_data_status data; > > int rc; > > > > rc = __sev_do_cmd_locked(SEV_CMD_PLATFORM_STATUS, &data, error); > > if (rc) > > return rc; > > > > *state = data.state; <--- State could be null. > > No, because this is an internal helper and all call sites can be easily audited. > > > return rc; > > } > > ``` > > > > Example outside of this driver: > > https://elixir.bootlin.com/linux/v5.15.1/source/arch/x86/kvm/x86.c#L468 > > > > ``` > > int kvm_set_apic_base(struct kvm_vcpu *vcpu, struct msr_data *msr_info) > > { > > enum lapic_mode old_mode = kvm_get_apic_mode(vcpu); > > enum lapic_mode new_mode = kvm_apic_mode(msr_info->data); <--- > > msr_info could be null here > > u64 reserved_bits = kvm_vcpu_reserved_gpa_bits_raw(vcpu) | 0x2ff | > > (guest_cpuid_has(vcpu, X86_FEATURE_X2APIC) ? 0 : X2APIC_ENABLE); > > > > if ((msr_info->data & reserved_bits) != 0 || new_mode == LAPIC_MODE_INVALID) > > return 1; > > if (!msr_info->host_initiated) { > > if (old_mode == LAPIC_MODE_X2APIC && new_mode == LAPIC_MODE_XAPIC) > > return 1; > > if (old_mode == LAPIC_MODE_DISABLED && new_mode == LAPIC_MODE_X2APIC) > > return 1; > > } > > > > kvm_lapic_set_base(vcpu, msr_info->data); > > kvm_recalculate_apic_map(vcpu->kvm); > > return 0; > > } > > EXPORT_SYMBOL_GPL(kvm_set_apic_base); > > ``` > > The difference is that KVM has consistent expecations for a set of functions, > whereas sev-dev.c does not. Yes, KVM will explode if @msr_info is NULL, and > there are undoubtedly a bajillion flows in the kernel that would do the same, > but unlike the functions declared in include/linux/psp-sev.h() the requirements > on the caller are fairly obvious. E.g. why should this be illegal from a caller's > perspective? > > sev_platform_init(NULL); > sev_platform_status(&status, NULL); Ack. I'll store a intermediate error in __sev_platform_init_locked and export to @error if its not null.