On 03.02.20 14:19, Christian Borntraeger wrote:
> From: Janosch Frank <frankja@xxxxxxxxxxxxx>
>
> The SPX instruction is handled by the ulravisor. We do get a
> notification intercept, though. Let us update our internal view.
>
> In addition to that, when the guest prefix page is not secure, an
> intercept 112 (0x70) is indicated. To avoid this for the most common
> cases, we can make the guest prefix page protected whenever we pin it.
> We have to deal with 112 nevertheless, e.g. when some host code triggers
> an export (e.g. qemu dump guest memory). We can simply re-run the
> pinning logic by doing a no-op prefix change.
>
> Signed-off-by: Janosch Frank <frankja@xxxxxxxxxxxxx>
> ---
> arch/s390/include/asm/kvm_host.h | 1 +
> arch/s390/kvm/intercept.c | 15 +++++++++++++++
> arch/s390/kvm/kvm-s390.c | 14 ++++++++++++++
> 3 files changed, 30 insertions(+)
>
> diff --git a/arch/s390/include/asm/kvm_host.h b/arch/s390/include/asm/kvm_host.h
> index 48f382680755..686b00ced55b 100644
> --- a/arch/s390/include/asm/kvm_host.h
> +++ b/arch/s390/include/asm/kvm_host.h
> @@ -225,6 +225,7 @@ struct kvm_s390_sie_block {
> #define ICPT_PV_INT_EN 0x64
> #define ICPT_PV_INSTR 0x68
> #define ICPT_PV_NOTIF 0x6c
> +#define ICPT_PV_PREF 0x70
> __u8 icptcode; /* 0x0050 */
> __u8 icptstatus; /* 0x0051 */
> __u16 ihcpu; /* 0x0052 */
> diff --git a/arch/s390/kvm/intercept.c b/arch/s390/kvm/intercept.c
> index d63f9cf10360..ceba0abb1900 100644
> --- a/arch/s390/kvm/intercept.c
> +++ b/arch/s390/kvm/intercept.c
> @@ -451,6 +451,15 @@ static int handle_operexc(struct kvm_vcpu *vcpu)
> return kvm_s390_inject_program_int(vcpu, PGM_OPERATION);
> }
>
> +static int handle_pv_spx(struct kvm_vcpu *vcpu)
> +{
> + u32 pref = *(u32 *)vcpu->arch.sie_block->sidad;
> +
> + kvm_s390_set_prefix(vcpu, pref);
> + trace_kvm_s390_handle_prefix(vcpu, 1, pref);
> + return 0;
> +}
> +
> static int handle_pv_sclp(struct kvm_vcpu *vcpu)
> {
> struct kvm_s390_float_interrupt *fi = &vcpu->kvm->arch.float_int;
> @@ -475,6 +484,8 @@ static int handle_pv_sclp(struct kvm_vcpu *vcpu)
>
> static int handle_pv_not(struct kvm_vcpu *vcpu)
> {
> + if (vcpu->arch.sie_block->ipa == 0xb210)
> + return handle_pv_spx(vcpu);
> if (vcpu->arch.sie_block->ipa == 0xb220)
> return handle_pv_sclp(vcpu);
>
> @@ -533,6 +544,10 @@ int kvm_handle_sie_intercept(struct kvm_vcpu *vcpu)
> case ICPT_PV_NOTIF:
> rc = handle_pv_not(vcpu);
> break;
> + case ICPT_PV_PREF:
> + rc = 0;
> + kvm_s390_set_prefix(vcpu, kvm_s390_get_prefix(vcpu));
/me confused
This is the "request to map prefix" case, right?
I'd *really* prefer to have a comment and a manual
/* request to convert and pin the prefix pages again */
kvm_make_request(KVM_REQ_MMU_RELOAD, vcpu)
A TLB flush is IMHO not necessary, as the prefix did not change.
> + break;
> default:
> return -EOPNOTSUPP;
> }
> diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
> index 76303b0f1226..6e74c7afae3a 100644
> --- a/arch/s390/kvm/kvm-s390.c
> +++ b/arch/s390/kvm/kvm-s390.c
> @@ -3675,6 +3675,20 @@ static int kvm_s390_handle_requests(struct kvm_vcpu *vcpu)
> rc = gmap_mprotect_notify(vcpu->arch.gmap,
> kvm_s390_get_prefix(vcpu),
> PAGE_SIZE * 2, PROT_WRITE);
> + if (!rc && kvm_s390_pv_is_protected(vcpu->kvm)) {
> + do {
> + rc = uv_convert_to_secure(
> + vcpu->arch.gmap,
> + kvm_s390_get_prefix(vcpu));
> + } while (rc == -EAGAIN);
> + WARN_ONCE(rc, "Error while importing first prefix page. rc %d", rc);
> + do {
> + rc = uv_convert_to_secure(
> + vcpu->arch.gmap,
> + kvm_s390_get_prefix(vcpu) + PAGE_SIZE);
> + } while (rc == -EAGAIN);
> + WARN_ONCE(rc, "Error while importing second prefix page. rc %d", rc);
Maybe factor that out into a separate function (e.g., for a single page
and call that twice).
> + }
> if (rc) {
> kvm_make_request(KVM_REQ_MMU_RELOAD, vcpu);
> return rc;
>
--
Thanks,
David / dhildenb
