On 23.02.21 20:13, Claudio Imbrenda wrote:
Correctly handle the MVPG instruction when issued by a VSIE guest.
Fixes: a3508fbe9dc6d ("KVM: s390: vsie: initial support for nested
virtualization")
Cc: sta...@vger.kernel.org
Signed-off-by: Claudio Imbrenda <imbre...@linux.ibm.com>
Acked-by: Janosch Frank <fran...@linux.ibm.com>
---
arch/s390/kvm/vsie.c | 93 +++++++++++++++++++++++++++++++++++++++++---
1 file changed, 88 insertions(+), 5 deletions(-)
diff --git a/arch/s390/kvm/vsie.c b/arch/s390/kvm/vsie.c
index 78b604326016..dbf4241bc2dc 100644
--- a/arch/s390/kvm/vsie.c
+++ b/arch/s390/kvm/vsie.c
@@ -417,11 +417,6 @@ static void unshadow_scb(struct kvm_vcpu *vcpu, struct
vsie_page *vsie_page)
memcpy((void *)((u64)scb_o + 0xc0),
(void *)((u64)scb_s + 0xc0), 0xf0 - 0xc0);
break;
- case ICPT_PARTEXEC:
- /* MVPG only */
- memcpy((void *)((u64)scb_o + 0xc0),
- (void *)((u64)scb_s + 0xc0), 0xd0 - 0xc0);
- break;
}
if (scb_s->ihcpu != 0xffffU)
@@ -983,6 +978,90 @@ static int handle_stfle(struct kvm_vcpu *vcpu, struct
vsie_page *vsie_page)
return 0;
}
+static u64 vsie_get_register(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page, u8 reg)
+{
+ reg &= 0xf;
Nit, I'd mask of that value in the caller where you extract it from the ipb.
...
+static int vsie_handle_mvpg(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page)
+{
+ struct kvm_s390_sie_block *scb_s = &vsie_page->scb_s;
+ unsigned long pei_dest, pei_src, src, dest, mask = PAGE_MASK;
+ u64 *pei_block = &vsie_page->scb_o->mcic;
+ int edat, rc_dest, rc_src;
+ union ctlreg0 cr0;
...
const uint8_t r1 = (scb_s->ipb >> 16) & 0xf;
const uint8_t r3 = (scb_s->ipb >> 20) & 0xf;
(note: r1/r3 is just a guess ;) - and having the actual identifiers here
will make the code easier to understand)
+
+ cr0.val = vcpu->arch.sie_block->gcr[0];
+ edat = cr0.edat && test_kvm_facility(vcpu->kvm, 8);
+ if (psw_bits(scb_s->gpsw).eaba == PSW_BITS_AMODE_24BIT)
What about factoring out that masking like
kvm_s390_logical_to_effective()
introduce
vsie_logical_to_effective()
to handle that.
+ mask = 0xfff000;
+ else if (psw_bits(scb_s->gpsw).eaba == PSW_BITS_AMODE_31BIT)
+ mask = 0x7ffff000;
+
+ dest = vsie_get_register(vcpu, vsie_page, scb_s->ipb >> 16) & mask;
+ src = vsie_get_register(vcpu, vsie_page, scb_s->ipb >> 20) & mask;
+
+ rc_dest = kvm_s390_shadow_fault(vcpu, vsie_page->gmap, dest, &pei_dest);
+ rc_src = kvm_s390_shadow_fault(vcpu, vsie_page->gmap, src, &pei_src);
+ /*
+ * Either everything went well, or something non-critical went wrong
+ * e.g. beause of a race. In either case, simply retry.
s/beause/because/
+ */
+ if (rc_dest == -EAGAIN || rc_src == -EAGAIN || (!rc_dest && !rc_src)) {
+ retry_vsie_icpt(vsie_page);
+ return -EAGAIN;
I remember, because of the retry_vsie_icpt() you can simply return 0.
Whatever you prefer.
+ }
+ /* Something more serious went wrong, propagate the error */
+ if (rc_dest < 0)
+ return rc_dest;
+ if (rc_src < 0)
+ return rc_src;
+
+ /* The only possible suppressing exception: just deliver it */
+ if (rc_dest == PGM_TRANSLATION_SPEC || rc_src == PGM_TRANSLATION_SPEC) {
+ clear_vsie_icpt(vsie_page);
+ rc_dest = kvm_s390_inject_program_int(vcpu,
PGM_TRANSLATION_SPEC);
+ WARN_ON_ONCE(rc_dest);
+ return 1;
+ }
+
+ /*
+ * Forward the PEI intercept to the guest if it was a page fault, or
+ * also for segment and region table faults if EDAT applies.
+ */
+ if (edat) {
+ rc_dest = rc_dest == PGM_ASCE_TYPE ? rc_dest : 0;
+ rc_src = rc_src == PGM_ASCE_TYPE ? rc_src : 0;
+ } else {
+ rc_dest = rc_dest != PGM_PAGE_TRANSLATION ? rc_dest : 0;
+ rc_src = rc_src != PGM_PAGE_TRANSLATION ? rc_src : 0;
+ }
+ if (!rc_dest && !rc_src) {
+ pei_block[0] = pei_dest;
+ pei_block[1] = pei_src;
+ return 1;
+ }
+
+ retry_vsie_icpt(vsie_page);
+
+ /*
+ * The host has edat, and the guest does not, or it was an ASCE type
+ * exception. The host needs to inject the appropriate DAT interrupts
+ * into the guest.
+ */
+ if (rc_dest)
+ return inject_fault(vcpu, rc_dest, dest, 1);
+ return inject_fault(vcpu, rc_src, src, 0);
The rc_dest and rc_src handling towards the end is a little confusing,
but I have no real suggestion to make it easier to digest.
Only some suggestions to make the code a bit nicer to read. Apart from
that LGTM.
Reviewed-by: David Hildenbrand <da...@redhat.com>
--
Thanks,
David / dhildenb
