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SubjectRe: [PATCH RFC 2/2] KVM: s390: introduce and use KVM_REQ_VSIE_RESTART
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On 07/08/2018 14:51, David Hildenbrand wrote:
> When we change the crycb (or execution controls), we also have to make sure
> that the vSIE shadow datastructures properly consider the changed
> values before rerunning the vSIE. We can achieve that by simply using a
> VCPU request now.
>
> This has to be a synchronous request (== handled before entering the
> (v)SIE again).
>
> The request will make sure that the vSIE handler is left, and that the
> request will be processed (NOP), therefore forcing a reload of all
> vSIE data (including rebuilding the crycb) when re-entering the vSIE
> interception handler the next time.
>
> Signed-off-by: David Hildenbrand <david@redhat.com>
> ---
> arch/s390/include/asm/kvm_host.h | 1 +
> arch/s390/kvm/kvm-s390.c | 7 ++++++-
> 2 files changed, 7 insertions(+), 1 deletion(-)
>
> diff --git a/arch/s390/include/asm/kvm_host.h b/arch/s390/include/asm/kvm_host.h
> index 29c940bf8506..75d39628f21d 100644
> --- a/arch/s390/include/asm/kvm_host.h
> +++ b/arch/s390/include/asm/kvm_host.h
> @@ -44,6 +44,7 @@
> #define KVM_REQ_ICPT_OPEREXC KVM_ARCH_REQ(2)
> #define KVM_REQ_START_MIGRATION KVM_ARCH_REQ(3)
> #define KVM_REQ_STOP_MIGRATION KVM_ARCH_REQ(4)
> +#define KVM_REQ_VSIE_RESTART KVM_ARCH_REQ(5)
>
> #define SIGP_CTRL_C 0x80
> #define SIGP_CTRL_SCN_MASK 0x3f
> diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
> index c87734a31fdb..2fdc017d91f0 100644
> --- a/arch/s390/kvm/kvm-s390.c
> +++ b/arch/s390/kvm/kvm-s390.c
> @@ -842,8 +842,11 @@ void kvm_s390_vcpu_crypto_reset_all(struct kvm *kvm)
>
> kvm_s390_vcpu_block_all(kvm);
>
> - kvm_for_each_vcpu(i, vcpu, kvm)
> + kvm_for_each_vcpu(i, vcpu, kvm) {
> kvm_s390_vcpu_crypto_setup(vcpu);
> + /* recreate the shadow crycb by leaving the VSIE handler */
> + kvm_s390_sync_request(KVM_REQ_VSIE_RESTART, vcpu);
> + }
>
> kvm_s390_vcpu_unblock_all(kvm);
> }
> @@ -3201,6 +3204,8 @@ static int kvm_s390_handle_requests(struct kvm_vcpu *vcpu)
>
> /* nothing to do, just clear the request */
> kvm_clear_request(KVM_REQ_UNHALT, vcpu);
> + /* we left the vsie handler, nothing to do, just clear the request */
> + kvm_clear_request(KVM_REQ_VSIE_RESTART, vcpu);
>
> return 0;
> }

Reviewed-by: Pierre Morel<pmorel@linux.ibm.com>
Tested-by: Pierre Morel<pmorel@linux.ibm.com>


--
Pierre Morel
Linux/KVM/QEMU in Böblingen - Germany

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