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Violators will be prosecuted for from ; Tue, 25 Feb 2020 12:51:21 -0000 Subject: Re: [PATCH v4 24/36] KVM: s390: protvirt: Do only reset registers that are accessible References: <20200224114107.4646-1-borntraeger@de.ibm.com> <20200224114107.4646-25-borntraeger@de.ibm.com> <20200225133252.479644ea.cohuck@redhat.com> From: Janosch Frank Date: Tue, 25 Feb 2020 13:51:12 +0100 MIME-Version: 1.0 In-Reply-To: <20200225133252.479644ea.cohuck@redhat.com> Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="tkTdvCNkSbMOvKXiR3mNE5Z0kItvAA2TI" Message-Id: <4726aa70-7c53-1985-8ada-3bfbea57e72f@linux.ibm.com> Sender: linux-s390-owner@vger.kernel.org List-ID: To: Cornelia Huck , Christian Borntraeger Cc: Janosch Frank , KVM , David Hildenbrand , Thomas Huth , Ulrich Weigand , Claudio Imbrenda , linux-s390 , Michael Mueller , Vasily Gorbik This is an OpenPGP/MIME signed message (RFC 4880 and 3156) --tkTdvCNkSbMOvKXiR3mNE5Z0kItvAA2TI Content-Type: multipart/mixed; boundary="CFEk8beRRdEtdlMFbFsdnMLG6vJieC0pu" --CFEk8beRRdEtdlMFbFsdnMLG6vJieC0pu Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: quoted-printable On 2/25/20 1:32 PM, Cornelia Huck wrote: > On Mon, 24 Feb 2020 06:40:55 -0500 > Christian Borntraeger wrote: >=20 >> From: Janosch Frank >> >> For protected VMs the hypervisor can not access guest breaking event >> address, program parameter, bpbc and todpr. Do not reset those fields >> as the control block does not provide access to these fields. >> >> Signed-off-by: Janosch Frank >> Reviewed-by: David Hildenbrand >> [borntraeger@de.ibm.com: patch merging, splitting, fixing] >> Signed-off-by: Christian Borntraeger >> --- >> arch/s390/kvm/kvm-s390.c | 10 ++++++---- >> 1 file changed, 6 insertions(+), 4 deletions(-) >> >> diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c >> index 6ab4c88f2e1d..c734e89235f9 100644 >> --- a/arch/s390/kvm/kvm-s390.c >> +++ b/arch/s390/kvm/kvm-s390.c >> @@ -3499,14 +3499,16 @@ static void kvm_arch_vcpu_ioctl_initial_reset(= struct kvm_vcpu *vcpu) >> kvm_s390_set_prefix(vcpu, 0); >> kvm_s390_set_cpu_timer(vcpu, 0); >> vcpu->arch.sie_block->ckc =3D 0; >> - vcpu->arch.sie_block->todpr =3D 0; >> memset(vcpu->arch.sie_block->gcr, 0, sizeof(vcpu->arch.sie_block->gc= r)); >> vcpu->arch.sie_block->gcr[0] =3D CR0_INITIAL_MASK; >> vcpu->arch.sie_block->gcr[14] =3D CR14_INITIAL_MASK; >> vcpu->run->s.regs.fpc =3D 0; >> - vcpu->arch.sie_block->gbea =3D 1; >> - vcpu->arch.sie_block->pp =3D 0; >> - vcpu->arch.sie_block->fpf &=3D ~FPF_BPBC; >> + if (!kvm_s390_pv_cpu_is_protected(vcpu)) { >> + vcpu->arch.sie_block->gbea =3D 1; >> + vcpu->arch.sie_block->pp =3D 0; >> + vcpu->arch.sie_block->fpf &=3D ~FPF_BPBC; >> + vcpu->arch.sie_block->todpr =3D 0; >=20 > What happens if we do change those values? Is it just ignored or will > we get an exception on the next SIE entry? Well, changing gbea is a bad idea because of the sida overlay. I don't think that any other is checked, but I'd need to look up the todpr changes to be completely sure. >=20 >> + } >> } >> =20 >> static void kvm_arch_vcpu_ioctl_clear_reset(struct kvm_vcpu *vcpu) >=20 --CFEk8beRRdEtdlMFbFsdnMLG6vJieC0pu-- --tkTdvCNkSbMOvKXiR3mNE5Z0kItvAA2TI Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- iQIzBAEBCAAdFiEEwGNS88vfc9+v45Yq41TmuOI4ufgFAl5VGEEACgkQ41TmuOI4 ufg0ShAApH/Q66NtLPlZ5Tg1Ds55t09/GFrr7EdYH0+gms2E16rPoFAVkNnRcJHv c5aC/K8Nkh+TmrQDoXPUCN5d2kwu3YcyIz3KkoDrxM9Yw6aeIk+09NhHgupRbdk7 xA1H2LCDcMhSWB7r67gs9FRjP4rYVSfqfrFZJVh2hsWaoSDjanBsvFLa5YUaCQ06 8gyUGVROPV+szsJ03VHwoXCIKYmQx/6aw4uZCeXw4IZ499cq8ozTd1CZLsEoqoZO rrj5PTPwoB7nmqf0vYk7GBQRjaZZrjjVFTTAq4UAI5x8qvj6psJMqorZdf55JYgB Fei1lDB1ipeu2/aBegG6WrbgF8mR9MKMFUeln/eYszmoLjbJURjobl0CmO068wia bZCmG/hYqDtSG9a/SyZequdR+IkkZoZMNnINI8OzblQXVQ0LGq1l6DZEWymoTHlx rEA0h2/ceQZNxkHGvScgrIZoRbls4fqvdg+77PkStwvVG5LvVsLQOLfE0HNYgYDQ kZ7sh8jf4ezgefXcH8BiYG/r7g83Rp/A6u2mWyJ3o+tSS65rxShG1rR5Q15pC7It ipdxd7V9bTHvm963YR1aQktxgiKjCYVLHg3x3mr8/p690QtK0c9Mz5nbnaho5Ve2 ogl9Zr/KZu8gQPh/9afbrzc/xOl2YsgCoZYe/h0qN23QUzGVD/M= =Tfev -----END PGP SIGNATURE----- --tkTdvCNkSbMOvKXiR3mNE5Z0kItvAA2TI--