Messages in this thread | | | Subject | Re: [PATCH v2 02/15] s390: vsie: implement AP support for second level guest | From | Pierre Morel <> | Date | Wed, 28 Feb 2018 11:03:52 +0100 |
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On 28/02/2018 10:39, David Hildenbrand wrote: > On 27.02.2018 15:28, Tony Krowiak wrote: >> Set effective masks and CRYCB format in the shadow copy of the >> guest level 2 CRYCB. >> >> Signed-off-by: Tony Krowiak <akrowiak@linux.vnet.ibm.com> >> --- >> arch/s390/include/asm/kvm-ap.h | 2 + >> arch/s390/kvm/kvm-ap.c | 5 +++ >> arch/s390/kvm/vsie.c | 71 +++++++++++++++++++++++++++++++++------- >> 3 files changed, 66 insertions(+), 12 deletions(-) >> >> diff --git a/arch/s390/include/asm/kvm-ap.h b/arch/s390/include/asm/kvm-ap.h >> index 4e43117..ef749e7 100644 >> --- a/arch/s390/include/asm/kvm-ap.h >> +++ b/arch/s390/include/asm/kvm-ap.h >> @@ -13,4 +13,6 @@ >> >> void kvm_ap_set_crycb_format(struct kvm *kvm, __u32 *crycbd); >> >> +int kvm_ap_get_crycb_format(struct kvm *kvm); >> + >> #endif /* _ASM_KVM_AP */ >> diff --git a/arch/s390/kvm/kvm-ap.c b/arch/s390/kvm/kvm-ap.c >> index 5305f4c..bafe63b 100644 >> --- a/arch/s390/kvm/kvm-ap.c >> +++ b/arch/s390/kvm/kvm-ap.c >> @@ -11,6 +11,11 @@ >> >> #include "kvm-s390.h" >> >> +int kvm_ap_get_crycb_format(struct kvm *kvm) >> +{ >> + return kvm->arch.crypto.crycbd & CRYCB_FORMAT_MASK; >> +} > Why exactly do we need this function? If there are no other users, just > do it directly in the code below. > >> + >> static int kvm_ap_apxa_installed(void) >> { >> int ret; >> diff --git a/arch/s390/kvm/vsie.c b/arch/s390/kvm/vsie.c >> index 8961e39..93076ba 100644 >> --- a/arch/s390/kvm/vsie.c >> +++ b/arch/s390/kvm/vsie.c >> @@ -18,6 +18,7 @@ >> #include <asm/sclp.h> >> #include <asm/nmi.h> >> #include <asm/dis.h> >> +#include <asm/kvm-ap.h> >> #include "kvm-s390.h" >> #include "gaccess.h" >> >> @@ -137,12 +138,56 @@ static int prepare_cpuflags(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page) >> } >> >> /* >> + * Set up the effective masks for the shadow copy of the crycb. The effective >> + * masks for guest 3 are set by performing a logical bitwise AND of the guest 3 >> + * masks with the guest 2 masks. >> + */ >> +static void set_crycb_emasks(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page) >> +{ >> + int fmt = kvm_ap_get_crycb_format(vcpu->kvm); >> + unsigned long *mask1, *mask2; >> + >> + switch (fmt) { >> + case CRYCB_FORMAT1: >> + case CRYCB_FORMAT2: > Assume L2 gave us FORMAT0 and we are using FORMAT2. You would copy wrong > bits. See below, maybe we need conversion. +1 and in the case we have FORTMAT1 in L2 and/or L3, you also copy them from and/or to the wrong place.
> >> + mask1 = (unsigned long *)vsie_page->crycb.apcb1.apm; >> + mask2 = (unsigned long *) >> + vcpu->kvm->arch.crypto.crycb->apcb1.apm; >> + bitmap_and(mask1, mask1, mask2, APCB1_MASK_SIZE); >> + >> + mask1 = (unsigned long *)vsie_page->crycb.apcb1.aqm; >> + mask2 = (unsigned long *) >> + vcpu->kvm->arch.crypto.crycb->apcb1.aqm; >> + bitmap_and(mask1, mask1, mask2, APCB1_MASK_SIZE); >> + >> + mask1 = (unsigned long *)vsie_page->crycb.apcb1.adm; >> + mask2 = (unsigned long *) >> + vcpu->kvm->arch.crypto.crycb->apcb1.adm; >> + bitmap_and(mask1, mask1, mask2, APCB1_MASK_SIZE); >> + break; >> + default: >> + mask1 = (unsigned long *)vsie_page->crycb.apcb0.apm; >> + mask2 = (unsigned long *) >> + vcpu->kvm->arch.crypto.crycb->apcb1.apm; >> + bitmap_and(mask1, mask1, mask2, APCB0_MASK_SIZE); >> + >> + mask1 = (unsigned long *)vsie_page->crycb.apcb0.aqm; >> + mask2 = (unsigned long *) >> + vcpu->kvm->arch.crypto.crycb->apcb1.aqm; >> + bitmap_and(mask1, mask1, mask2, APCB0_MASK_SIZE); >> + >> + mask1 = (unsigned long *)vsie_page->crycb.apcb0.adm; >> + mask2 = (unsigned long *) >> + vcpu->kvm->arch.crypto.crycb->apcb1.adm; >> + bitmap_and(mask1, mask1, mask2, APCB0_MASK_SIZE); >> + break; >> + } >> +} >> + >> +/* >> * Create a shadow copy of the crycb block and setup key wrapping, if >> * requested for guest 3 and enabled for guest 2. >> * >> - * We only accept format-1 (no AP in g2), but convert it into format-2 >> - * There is nothing to do for format-0. >> - * >> * Returns: - 0 if shadowed or nothing to do >> * - > 0 if control has to be given to guest 2 >> */ >> @@ -155,9 +200,17 @@ static int shadow_crycb(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page) >> unsigned long *b1, *b2; >> u8 ecb3_flags; >> >> - scb_s->crycbd = 0; >> - if (!(crycbd_o & vcpu->arch.sie_block->crycbd & CRYCB_FORMAT1)) >> - return 0; >> + scb_s->crycbd = ((__u32)(__u64) &vsie_page->crycb); >> + kvm_ap_set_crycb_format(vcpu->kvm, &scb_s->crycbd); >> + >> + /* copy the crycb */ >> + if (read_guest_real(vcpu, crycb_addr, &vsie_page->crycb, >> + sizeof(vsie_page->crycb))) >> + return set_validity_icpt(scb_s, 0x0035U); > This looks wrong. You are always copying from L2, although L2 might not > even set up a crycb for L3. You removed the important crycbd_o check. > > Don't we need the following? > > a) Determine the _allowed_ crycb format for L2 -> L3. (How can we tell > which format L2 is allowed to use for L3) > b) Determine the target crycb format. This is basically > vm_ap_set_crycb_format afaics. > c) Convert the given crycb to the target crycb format. > > So importantly, can you clarify (as I don't have access to documentation): > > - When is L2 allowed to use format-0? So when will the format not be > ignored but is actually used? > > - When is L2 allowed to use fortma-2? So when will the format not be > ignored but is actually used? > > - When does the SIE start interpreting AP instructions? So how can we > hinder it from doing so? Empty masks? crycb format? > >> + >> + /* set up the effective masks */ >> + set_crycb_emasks(vcpu, vsie_page); >> + >> /* format-1 is supported with message-security-assist extension 3 */ >> if (!test_kvm_facility(vcpu->kvm, 76)) >> return 0; > You now already copied the wrapping keys. So they could be !0. Please > add a comment why we don't care. > > /* wrapping keys are ignored without ECB3_AES / ECB3_DEA */ > >> @@ -172,13 +225,7 @@ static int shadow_crycb(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page) >> else if (!crycb_addr) >> return set_validity_icpt(scb_s, 0x0039U); >> >> - /* copy only the wrapping keys */ >> - if (read_guest_real(vcpu, crycb_addr + 72, &vsie_page->crycb, 56)) >> - return set_validity_icpt(scb_s, 0x0035U); >> - >> scb_s->ecb3 |= ecb3_flags; >> - scb_s->crycbd = ((__u32)(__u64) &vsie_page->crycb) | CRYCB_FORMAT1 | >> - CRYCB_FORMAT2; >> >> /* xor both blocks in one run */ >> b1 = (unsigned long *) vsie_page->crycb.dea_wrapping_key_mask; >> >
-- Pierre Morel Linux/KVM/QEMU in Böblingen - Germany
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