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KVM: s390: vsie: support STFLE interpretation
Issuing STFLE is extremely rare. Instead of copying 2k on every VSIE call, let's do this lazily, when a guest 3 tries to execute STFLE. We can setup the block and retry. Unfortunately, we can't directly forward that facility list, as we only have a 31 bit address for the facility list designation. So let's use a DMA allocation for our vsie_page instead for now. Acked-by: Christian Borntraeger <borntraeger@de.ibm.com> Signed-off-by: David Hildenbrand <dahi@linux.vnet.ibm.com> Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
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4ceafa9027
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1 changed files with 47 additions and 2 deletions
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@ -18,6 +18,7 @@
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#include <asm/mmu_context.h>
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#include <asm/sclp.h>
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#include <asm/nmi.h>
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#include <asm/dis.h>
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#include "kvm-s390.h"
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#include "gaccess.h"
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@ -27,7 +28,8 @@ struct vsie_page {
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struct kvm_s390_sie_block *scb_o; /* 0x0200 */
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/* the shadow gmap in use by the vsie_page */
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struct gmap *gmap; /* 0x0208 */
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__u8 reserved[0x1000 - 0x0210]; /* 0x0210 */
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__u8 reserved[0x0800 - 0x0210]; /* 0x0210 */
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__u8 fac[S390_ARCH_FAC_LIST_SIZE_BYTE]; /* 0x0800 */
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} __packed;
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/* trigger a validity icpt for the given scb */
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@ -194,6 +196,7 @@ static int shadow_scb(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page)
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scb_s->ecb2 = 0;
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scb_s->ecb3 = 0;
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scb_s->ecd = 0;
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scb_s->fac = 0;
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rc = prepare_cpuflags(vcpu, vsie_page);
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if (rc)
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@ -521,6 +524,44 @@ static inline void clear_vsie_icpt(struct vsie_page *vsie_page)
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vsie_page->scb_s.icptcode = 0;
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}
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/* rewind the psw and clear the vsie icpt, so we can retry execution */
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static void retry_vsie_icpt(struct vsie_page *vsie_page)
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{
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struct kvm_s390_sie_block *scb_s = &vsie_page->scb_s;
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int ilen = insn_length(scb_s->ipa >> 8);
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/* take care of EXECUTE instructions */
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if (scb_s->icptstatus & 1) {
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ilen = (scb_s->icptstatus >> 4) & 0x6;
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if (!ilen)
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ilen = 4;
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}
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scb_s->gpsw.addr = __rewind_psw(scb_s->gpsw, ilen);
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clear_vsie_icpt(vsie_page);
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}
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/*
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* Try to shadow + enable the guest 2 provided facility list.
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* Retry instruction execution if enabled for and provided by guest 2.
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*
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* Returns: - 0 if handled (retry or guest 2 icpt)
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* - > 0 if control has to be given to guest 2
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*/
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static int handle_stfle(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page)
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{
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struct kvm_s390_sie_block *scb_s = &vsie_page->scb_s;
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__u32 fac = vsie_page->scb_o->fac & 0x7ffffff8U;
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if (fac && test_kvm_facility(vcpu->kvm, 7)) {
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retry_vsie_icpt(vsie_page);
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if (read_guest_real(vcpu, fac, &vsie_page->fac,
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sizeof(vsie_page->fac)))
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return set_validity_icpt(scb_s, 0x1090U);
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scb_s->fac = (__u32)(__u64) &vsie_page->fac;
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}
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return 0;
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}
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/*
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* Run the vsie on a shadow scb and a shadow gmap, without any further
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* sanity checks, handling SIE faults.
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@ -558,6 +599,10 @@ static int do_vsie_run(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page)
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return handle_fault(vcpu, vsie_page);
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switch (scb_s->icptcode) {
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case ICPT_INST:
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if (scb_s->ipa == 0xb2b0)
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rc = handle_stfle(vcpu, vsie_page);
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break;
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case ICPT_STOP:
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/* stop not requested by g2 - must have been a kick */
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if (!(atomic_read(&scb_o->cpuflags) & CPUSTAT_STOP_INT))
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@ -690,7 +735,7 @@ static struct vsie_page *get_vsie_page(struct kvm *kvm, unsigned long addr)
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mutex_lock(&kvm->arch.vsie.mutex);
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if (kvm->arch.vsie.page_count < nr_vcpus) {
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page = alloc_page(GFP_KERNEL | __GFP_ZERO);
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page = alloc_page(GFP_KERNEL | __GFP_ZERO | GFP_DMA);
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if (!page) {
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mutex_unlock(&kvm->arch.vsie.mutex);
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return ERR_PTR(-ENOMEM);
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