On 07.02.20 12:39, Christian Borntraeger wrote:
> From: Janosch Frank <frankja@xxxxxxxxxxxxx>
>
> The SPX instruction is handled by the ultravisor. 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>
> [borntraeger@xxxxxxxxxx: patch merging, splitting, fixing]
> Signed-off-by: Christian Borntraeger <borntraeger@xxxxxxxxxx>
> ---
> arch/s390/include/asm/kvm_host.h | 1 +
> arch/s390/kvm/intercept.c | 16 ++++++++++++++++
> arch/s390/kvm/kvm-s390.c | 14 ++++++++++++++
> 3 files changed, 31 insertions(+)
>
> diff --git a/arch/s390/include/asm/kvm_host.h b/arch/s390/include/asm/kvm_host.h
> index 05949ff75a1e..0e3ffad4137f 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_INT_ENABLE 0x64
> #define ICPT_PV_INSTR 0x68
> #define ICPT_PV_NOTIFY 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 db3dd5ee0b7a..2a966dc52611 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;
> @@ -477,6 +486,8 @@ static int handle_pv_sclp(struct kvm_vcpu *vcpu)
>
> static int handle_pv_notification(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);
>
> @@ -534,6 +545,11 @@ int kvm_handle_sie_intercept(struct kvm_vcpu *vcpu)
> case ICPT_PV_NOTIFY:
> rc = handle_pv_notification(vcpu);
> break;
> + case ICPT_PV_PREF:
> + rc = 0;
> + /* request to convert and pin the prefix pages again */
> + kvm_make_request(KVM_REQ_MMU_RELOAD, vcpu);
> + break;
> default:
> return -EOPNOTSUPP;
> }
> diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
> index 1797490e3e77..63d158149936 100644
> --- a/arch/s390/kvm/kvm-s390.c
> +++ b/arch/s390/kvm/kvm-s390.c
> @@ -3678,6 +3678,20 @@ 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);
I think it might be better to move this hunk in the ICPT_IV_PREF handler.
Then we can cleanup the convert to secure handling a bit.
> + }
> if (rc) {
> kvm_make_request(KVM_REQ_MMU_RELOAD, vcpu);
> return rc;
>
