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linux/arch/powerpc/kvm/book3s_hv_tm.c
Nicholas Piggin d82b392d9b KVM: PPC: Book3S HV Nested: Fix TM softpatch HFAC interrupt emulation 
Have the TM softpatch emulation code set up the HFAC interrupt and
return -1 in case an instruction was executed with HFSCR bits clear,
and have the interrupt exit handler fall through to the HFAC handler.
When the L0 is running a nested guest, this ensures the HFAC interrupt
is correctly passed up to the L1.

The "direct guest" exit handler will turn these into PROGILL program
interrupts so functionality in practice will be unchanged. But it's
possible an L1 would want to handle these in a different way.

Also rearrange the FAC interrupt emulation code to match the HFAC format
while here (mainly, adding the FSCR_INTR_CAUSE mask).

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210811160134.904987-5-npiggin@gmail.com
2021-08-25 16:37:17 +10:00

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// SPDX-License-Identifier: GPL-2.0-only
/*
* Copyright 2017 Paul Mackerras, IBM Corp. <paulus@au1.ibm.com>
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/kvm_host.h>
#include <asm/kvm_ppc.h>
#include <asm/kvm_book3s.h>
#include <asm/kvm_book3s_64.h>
#include <asm/reg.h>
#include <asm/ppc-opcode.h>
static void emulate_tx_failure(struct kvm_vcpu *vcpu, u64 failure_cause)
{
u64 texasr, tfiar;
u64 msr = vcpu->arch.shregs.msr;
tfiar = vcpu->arch.regs.nip & ~0x3ull;
texasr = (failure_cause << 56) | TEXASR_ABORT | TEXASR_FS | TEXASR_EXACT;
if (MSR_TM_SUSPENDED(vcpu->arch.shregs.msr))
texasr |= TEXASR_SUSP;
if (msr & MSR_PR) {
texasr |= TEXASR_PR;
tfiar |= 1;
}
vcpu->arch.tfiar = tfiar;
/* Preserve ROT and TL fields of existing TEXASR */
vcpu->arch.texasr = (vcpu->arch.texasr & 0x3ffffff) | texasr;
}
/*
* This gets called on a softpatch interrupt on POWER9 DD2.2 processors.
* We expect to find a TM-related instruction to be emulated. The
* instruction image is in vcpu->arch.emul_inst. If the guest was in
* TM suspended or transactional state, the checkpointed state has been
* reclaimed and is in the vcpu struct. The CPU is in virtual mode in
* host context.
*/
int kvmhv_p9_tm_emulation(struct kvm_vcpu *vcpu)
{
u32 instr = vcpu->arch.emul_inst;
u64 msr = vcpu->arch.shregs.msr;
u64 newmsr, bescr;
int ra, rs;
/*
* The TM softpatch interrupt sets NIP to the instruction following
* the faulting instruction, which is not executed. Rewind nip to the
* faulting instruction so it looks like a normal synchronous
* interrupt, then update nip in the places where the instruction is
* emulated.
*/
vcpu->arch.regs.nip -= 4;
/*
* rfid, rfebb, and mtmsrd encode bit 31 = 0 since it's a reserved bit
* in these instructions, so masking bit 31 out doesn't change these
* instructions. For treclaim., tsr., and trechkpt. instructions if bit
* 31 = 0 then they are per ISA invalid forms, however P9 UM, in section
* 4.6.10 Book II Invalid Forms, informs specifically that ignoring bit
* 31 is an acceptable way to handle these invalid forms that have
* bit 31 = 0. Moreover, for emulation purposes both forms (w/ and wo/
* bit 31 set) can generate a softpatch interrupt. Hence both forms
* are handled below for these instructions so they behave the same way.
*/
switch (instr & PO_XOP_OPCODE_MASK) {
case PPC_INST_RFID:
/* XXX do we need to check for PR=0 here? */
newmsr = vcpu->arch.shregs.srr1;
/* should only get here for Sx -> T1 transition */
WARN_ON_ONCE(!(MSR_TM_SUSPENDED(msr) &&
MSR_TM_TRANSACTIONAL(newmsr) &&
(newmsr & MSR_TM)));
newmsr = sanitize_msr(newmsr);
vcpu->arch.shregs.msr = newmsr;
vcpu->arch.cfar = vcpu->arch.regs.nip;
vcpu->arch.regs.nip = vcpu->arch.shregs.srr0;
return RESUME_GUEST;
case PPC_INST_RFEBB:
if ((msr & MSR_PR) && (vcpu->arch.vcore->pcr & PCR_ARCH_206)) {
/* generate an illegal instruction interrupt */
kvmppc_core_queue_program(vcpu, SRR1_PROGILL);
return RESUME_GUEST;
}
/* check EBB facility is available */
if (!(vcpu->arch.hfscr & HFSCR_EBB)) {
vcpu->arch.hfscr &= ~HFSCR_INTR_CAUSE;
vcpu->arch.hfscr |= (u64)FSCR_EBB_LG << 56;
vcpu->arch.trap = BOOK3S_INTERRUPT_H_FAC_UNAVAIL;
return -1; /* rerun host interrupt handler */
}
if ((msr & MSR_PR) && !(vcpu->arch.fscr & FSCR_EBB)) {
/* generate a facility unavailable interrupt */
vcpu->arch.fscr &= ~FSCR_INTR_CAUSE;
vcpu->arch.fscr |= (u64)FSCR_EBB_LG << 56;
kvmppc_book3s_queue_irqprio(vcpu, BOOK3S_INTERRUPT_FAC_UNAVAIL);
return RESUME_GUEST;
}
bescr = vcpu->arch.bescr;
/* expect to see a S->T transition requested */
WARN_ON_ONCE(!(MSR_TM_SUSPENDED(msr) &&
((bescr >> 30) & 3) == 2));
bescr &= ~BESCR_GE;
if (instr & (1 << 11))
bescr |= BESCR_GE;
vcpu->arch.bescr = bescr;
msr = (msr & ~MSR_TS_MASK) | MSR_TS_T;
vcpu->arch.shregs.msr = msr;
vcpu->arch.cfar = vcpu->arch.regs.nip;
vcpu->arch.regs.nip = vcpu->arch.ebbrr;
return RESUME_GUEST;
case PPC_INST_MTMSRD:
/* XXX do we need to check for PR=0 here? */
rs = (instr >> 21) & 0x1f;
newmsr = kvmppc_get_gpr(vcpu, rs);
/* check this is a Sx -> T1 transition */
WARN_ON_ONCE(!(MSR_TM_SUSPENDED(msr) &&
MSR_TM_TRANSACTIONAL(newmsr) &&
(newmsr & MSR_TM)));
/* mtmsrd doesn't change LE */
newmsr = (newmsr & ~MSR_LE) | (msr & MSR_LE);
newmsr = sanitize_msr(newmsr);
vcpu->arch.shregs.msr = newmsr;
vcpu->arch.regs.nip += 4;
return RESUME_GUEST;
/* ignore bit 31, see comment above */
case (PPC_INST_TSR & PO_XOP_OPCODE_MASK):
/* check for PR=1 and arch 2.06 bit set in PCR */
if ((msr & MSR_PR) && (vcpu->arch.vcore->pcr & PCR_ARCH_206)) {
/* generate an illegal instruction interrupt */
kvmppc_core_queue_program(vcpu, SRR1_PROGILL);
return RESUME_GUEST;
}
/* check for TM disabled in the HFSCR or MSR */
if (!(vcpu->arch.hfscr & HFSCR_TM)) {
vcpu->arch.hfscr &= ~HFSCR_INTR_CAUSE;
vcpu->arch.hfscr |= (u64)FSCR_TM_LG << 56;
vcpu->arch.trap = BOOK3S_INTERRUPT_H_FAC_UNAVAIL;
return -1; /* rerun host interrupt handler */
}
if (!(msr & MSR_TM)) {
/* generate a facility unavailable interrupt */
vcpu->arch.fscr &= ~FSCR_INTR_CAUSE;
vcpu->arch.fscr |= (u64)FSCR_TM_LG << 56;
kvmppc_book3s_queue_irqprio(vcpu,
BOOK3S_INTERRUPT_FAC_UNAVAIL);
return RESUME_GUEST;
}
/* Set CR0 to indicate previous transactional state */
vcpu->arch.regs.ccr = (vcpu->arch.regs.ccr & 0x0fffffff) |
(((msr & MSR_TS_MASK) >> MSR_TS_S_LG) << 29);
/* L=1 => tresume, L=0 => tsuspend */
if (instr & (1 << 21)) {
if (MSR_TM_SUSPENDED(msr))
msr = (msr & ~MSR_TS_MASK) | MSR_TS_T;
} else {
if (MSR_TM_TRANSACTIONAL(msr))
msr = (msr & ~MSR_TS_MASK) | MSR_TS_S;
}
vcpu->arch.shregs.msr = msr;
vcpu->arch.regs.nip += 4;
return RESUME_GUEST;
/* ignore bit 31, see comment above */
case (PPC_INST_TRECLAIM & PO_XOP_OPCODE_MASK):
/* check for TM disabled in the HFSCR or MSR */
if (!(vcpu->arch.hfscr & HFSCR_TM)) {
vcpu->arch.hfscr &= ~HFSCR_INTR_CAUSE;
vcpu->arch.hfscr |= (u64)FSCR_TM_LG << 56;
vcpu->arch.trap = BOOK3S_INTERRUPT_H_FAC_UNAVAIL;
return -1; /* rerun host interrupt handler */
}
if (!(msr & MSR_TM)) {
/* generate a facility unavailable interrupt */
vcpu->arch.fscr &= ~FSCR_INTR_CAUSE;
vcpu->arch.fscr |= (u64)FSCR_TM_LG << 56;
kvmppc_book3s_queue_irqprio(vcpu,
BOOK3S_INTERRUPT_FAC_UNAVAIL);
return RESUME_GUEST;
}
/* If no transaction active, generate TM bad thing */
if (!MSR_TM_ACTIVE(msr)) {
kvmppc_core_queue_program(vcpu, SRR1_PROGTM);
return RESUME_GUEST;
}
/* If failure was not previously recorded, recompute TEXASR */
if (!(vcpu->arch.orig_texasr & TEXASR_FS)) {
ra = (instr >> 16) & 0x1f;
if (ra)
ra = kvmppc_get_gpr(vcpu, ra) & 0xff;
emulate_tx_failure(vcpu, ra);
}
copy_from_checkpoint(vcpu);
/* Set CR0 to indicate previous transactional state */
vcpu->arch.regs.ccr = (vcpu->arch.regs.ccr & 0x0fffffff) |
(((msr & MSR_TS_MASK) >> MSR_TS_S_LG) << 29);
vcpu->arch.shregs.msr &= ~MSR_TS_MASK;
vcpu->arch.regs.nip += 4;
return RESUME_GUEST;
/* ignore bit 31, see comment above */
case (PPC_INST_TRECHKPT & PO_XOP_OPCODE_MASK):
/* XXX do we need to check for PR=0 here? */
/* check for TM disabled in the HFSCR or MSR */
if (!(vcpu->arch.hfscr & HFSCR_TM)) {
vcpu->arch.hfscr &= ~HFSCR_INTR_CAUSE;
vcpu->arch.hfscr |= (u64)FSCR_TM_LG << 56;
vcpu->arch.trap = BOOK3S_INTERRUPT_H_FAC_UNAVAIL;
return -1; /* rerun host interrupt handler */
}
if (!(msr & MSR_TM)) {
/* generate a facility unavailable interrupt */
vcpu->arch.fscr &= ~FSCR_INTR_CAUSE;
vcpu->arch.fscr |= (u64)FSCR_TM_LG << 56;
kvmppc_book3s_queue_irqprio(vcpu,
BOOK3S_INTERRUPT_FAC_UNAVAIL);
return RESUME_GUEST;
}
/* If transaction active or TEXASR[FS] = 0, bad thing */
if (MSR_TM_ACTIVE(msr) || !(vcpu->arch.texasr & TEXASR_FS)) {
kvmppc_core_queue_program(vcpu, SRR1_PROGTM);
return RESUME_GUEST;
}
copy_to_checkpoint(vcpu);
/* Set CR0 to indicate previous transactional state */
vcpu->arch.regs.ccr = (vcpu->arch.regs.ccr & 0x0fffffff) |
(((msr & MSR_TS_MASK) >> MSR_TS_S_LG) << 29);
vcpu->arch.shregs.msr = msr | MSR_TS_S;
vcpu->arch.regs.nip += 4;
return RESUME_GUEST;
}
/* What should we do here? We didn't recognize the instruction */
kvmppc_core_queue_program(vcpu, SRR1_PROGILL);
pr_warn_ratelimited("Unrecognized TM-related instruction %#x for emulation", instr);
return RESUME_GUEST;
}
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