Am 27.06.24 um 11:23 schrieb Claudio Imbrenda:
On Thu, 27 Jun 2024 11:05:20 +0200 Christian Borntraeger <borntraeger@xxxxxxxxxxxxx> wrote:in rare cases, e.g. for injecting a machine check we do intercept all load PSW instructions via ICTL_LPSW. With facility 193 a new variant LPSWEY was added. KVM needs to handle that as well. Fixes: a3efa8429266 ("KVM: s390: gen_facilities: allow facilities 165, 193, 194 and 196") Reported-by: Marc Hartmayer <mhartmay@xxxxxxxxxxxxx> Signed-off-by: Christian Borntraeger <borntraeger@xxxxxxxxxxxxx>[...]+static inline u64 kvm_s390_get_base_disp_siy(struct kvm_vcpu *vcpu, u8 *ar) +{ + u32 base1 = vcpu->arch.sie_block->ipb >> 28; + u32 disp1 = ((vcpu->arch.sie_block->ipb & 0x0fff0000) >> 16) + + ((vcpu->arch.sie_block->ipb & 0xff00) << 4); + + /* The displacement is a 20bit _SIGNED_ value */ + if (disp1 & 0x80000) + disp1+=0xfff00000; + + if (ar) + *ar = base1; + + return (base1 ? vcpu->run->s.regs.gprs[base1] : 0) + (long)(int)disp1; +} + static inline void kvm_s390_get_base_disp_sse(struct kvm_vcpu *vcpu, u64 *address1, u64 *address2, u8 *ar_b1, u8 *ar_b2) diff --git a/arch/s390/kvm/priv.c b/arch/s390/kvm/priv.c index 1be19cc9d73c..1a49b89706f8 100644 --- a/arch/s390/kvm/priv.c +++ b/arch/s390/kvm/priv.c @@ -797,6 +797,36 @@ static int handle_lpswe(struct kvm_vcpu *vcpu) return 0; }+static int handle_lpswey(struct kvm_vcpu *vcpu)+{ + psw_t new_psw; + u64 addr; + int rc; + u8 ar; + + vcpu->stat.instruction_lpswey++; + + if (!test_kvm_facility(vcpu->kvm, 193)) + return kvm_s390_inject_program_int(vcpu, PGM_OPERATION); + + if (vcpu->arch.sie_block->gpsw.mask & PSW_MASK_PSTATE) + return kvm_s390_inject_program_int(vcpu, PGM_PRIVILEGED_OP); + + addr = kvm_s390_get_base_disp_siy(vcpu, &ar); + if (addr & 7) + return kvm_s390_inject_program_int(vcpu, PGM_SPECIFICATION); + + rc = read_guest(vcpu, addr, ar, &new_psw, sizeof(new_psw)); + if (rc) + return kvm_s390_inject_prog_cond(vcpu, rc); + + vcpu->arch.sie_block->gpsw = new_psw; + if (!is_valid_psw(&vcpu->arch.sie_block->gpsw)) + return kvm_s390_inject_program_int(vcpu, PGM_SPECIFICATION); + + return 0; +}looks quite straightforward, but you duplicated most of handle_lpswe. it would probably be cleaner to abstract the "load psw" logic, and convert handle_lpswe{,y} to be wrappers around it, something like static int _handle_load_psw(struct kvm_vcpu *vcpu, unsigned long pswaddr) which can then contain the old code from the "if (addr & 7)" to the end of the function. I think it would look cleaner, but I don't have a super strong opinion about it
As this is a functional fix needed to properly run z16 code I would like to minimize refactoring. I think we also need a different fix for LPSW(E) (we should set the BEAR register). We can do refactoring after we have fixed everything.
