1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * Copyright 2017 Paul Mackerras, IBM Corp. <paulus@au1.ibm.com>
4 */
5
6 #include <linux/kvm_host.h>
7
8 #include <asm/kvm_ppc.h>
9 #include <asm/kvm_book3s.h>
10 #include <asm/kvm_book3s_64.h>
11 #include <asm/reg.h>
12 #include <asm/ppc-opcode.h>
13
14 /*
15 * This handles the cases where the guest is in real suspend mode
16 * and we want to get back to the guest without dooming the transaction.
17 * The caller has checked that the guest is in real-suspend mode
18 * (MSR[TS] = S and the fake-suspend flag is not set).
19 */
20 int kvmhv_p9_tm_emulation_early(struct kvm_vcpu *vcpu)
21 {
22 u32 instr = vcpu->arch.emul_inst;
23 u64 newmsr, msr, bescr;
24 int rs;
25
26 /*
27 * rfid, rfebb, and mtmsrd encode bit 31 = 0 since it's a reserved bit
28 * in these instructions, so masking bit 31 out doesn't change these
29 * instructions. For the tsr. instruction if bit 31 = 0 then it is per
30 * ISA an invalid form, however P9 UM, in section 4.6.10 Book II Invalid
31 * Forms, informs specifically that ignoring bit 31 is an acceptable way
32 * to handle TM-related invalid forms that have bit 31 = 0. Moreover,
33 * for emulation purposes both forms (w/ and wo/ bit 31 set) can
34 * generate a softpatch interrupt. Hence both forms are handled below
35 * for tsr. to make them behave the same way.
36 */
37 switch (instr & PO_XOP_OPCODE_MASK) {
38 case PPC_INST_RFID:
39 /* XXX do we need to check for PR=0 here? */
40 newmsr = vcpu->arch.shregs.srr1;
41 /* should only get here for Sx -> T1 transition */
42 if (!(MSR_TM_TRANSACTIONAL(newmsr) && (newmsr & MSR_TM)))
43 return 0;
44 newmsr = sanitize_msr(newmsr);
45 vcpu->arch.shregs.msr = newmsr;
46 vcpu->arch.cfar = vcpu->arch.regs.nip - 4;
47 vcpu->arch.regs.nip = vcpu->arch.shregs.srr0;
48 return 1;
49
50 case PPC_INST_RFEBB:
51 /* check for PR=1 and arch 2.06 bit set in PCR */
52 msr = vcpu->arch.shregs.msr;
53 if ((msr & MSR_PR) && (vcpu->arch.vcore->pcr & PCR_ARCH_206))
54 return 0;
55 /* check EBB facility is available */
56 if (!(vcpu->arch.hfscr & HFSCR_EBB) ||
57 ((msr & MSR_PR) && !(mfspr(SPRN_FSCR) & FSCR_EBB)))
58 return 0;
59 bescr = mfspr(SPRN_BESCR);
60 /* expect to see a S->T transition requested */
61 if (((bescr >> 30) & 3) != 2)
62 return 0;
63 bescr &= ~BESCR_GE;
64 if (instr & (1 << 11))
65 bescr |= BESCR_GE;
66 mtspr(SPRN_BESCR, bescr);
67 msr = (msr & ~MSR_TS_MASK) | MSR_TS_T;
68 vcpu->arch.shregs.msr = msr;
69 vcpu->arch.cfar = vcpu->arch.regs.nip - 4;
70 vcpu->arch.regs.nip = mfspr(SPRN_EBBRR);
71 return 1;
72
73 case PPC_INST_MTMSRD:
74 /* XXX do we need to check for PR=0 here? */
75 rs = (instr >> 21) & 0x1f;
76 newmsr = kvmppc_get_gpr(vcpu, rs);
77 msr = vcpu->arch.shregs.msr;
78 /* check this is a Sx -> T1 transition */
79 if (!(MSR_TM_TRANSACTIONAL(newmsr) && (newmsr & MSR_TM)))
80 return 0;
81 /* mtmsrd doesn't change LE */
82 newmsr = (newmsr & ~MSR_LE) | (msr & MSR_LE);
83 newmsr = sanitize_msr(newmsr);
84 vcpu->arch.shregs.msr = newmsr;
85 return 1;
86
87 /* ignore bit 31, see comment above */
88 case (PPC_INST_TSR & PO_XOP_OPCODE_MASK):
89 /* we know the MSR has the TS field = S (0b01) here */
90 msr = vcpu->arch.shregs.msr;
91 /* check for PR=1 and arch 2.06 bit set in PCR */
92 if ((msr & MSR_PR) && (vcpu->arch.vcore->pcr & PCR_ARCH_206))
93 return 0;
94 /* check for TM disabled in the HFSCR or MSR */
95 if (!(vcpu->arch.hfscr & HFSCR_TM) || !(msr & MSR_TM))
96 return 0;
97 /* L=1 => tresume => set TS to T (0b10) */
98 if (instr & (1 << 21))
99 vcpu->arch.shregs.msr = (msr & ~MSR_TS_MASK) | MSR_TS_T;
100 /* Set CR0 to 0b0010 */
101 vcpu->arch.regs.ccr = (vcpu->arch.regs.ccr & 0x0fffffff) |
102 0x20000000;
103 return 1;
104 }
105
106 return 0;
107 }
108
109 /*
110 * This is called when we are returning to a guest in TM transactional
111 * state. We roll the guest state back to the checkpointed state.
112 */
113 void kvmhv_emulate_tm_rollback(struct kvm_vcpu *vcpu)
114 {
115 vcpu->arch.shregs.msr &= ~MSR_TS_MASK; /* go to N state */
116 vcpu->arch.regs.nip = vcpu->arch.tfhar;
117 copy_from_checkpoint(vcpu);
118 vcpu->arch.regs.ccr = (vcpu->arch.regs.ccr & 0x0fffffff) | 0xa0000000;
119 }
120
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