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After the L1 saves its PMU SPRs but before loading the L2's PMU SPRs, switch the pmcregs_in_use field in the L1 lppaca to the value advertised by the L2 in its VPA. On the way out of the L2, set it back after saving the L2 PMU registers (if they were in-use). This transfers the PMU liveness indication between the L1 and L2 at the points where the registers are not live. This fixes the nested HV bug for which a workaround was added to the L0 HV by commit63279eeb7f("KVM: PPC: Book3S HV: Always save guest pmu for guest capable of nesting"), which explains the problem in detail. That workaround is no longer required for guests that include this bug fix. Fixes:360cae3137("KVM: PPC: Book3S HV: Nested guest entry via hypercall") Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Reviewed-by: Fabiano Rosas <farosas@linux.ibm.com> Link: https://lore.kernel.org/r/20210811160134.904987-10-npiggin@gmail.com
53 lines
1.1 KiB
C
53 lines
1.1 KiB
C
/* SPDX-License-Identifier: GPL-2.0-or-later */
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/*
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* pmc.h
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* Copyright (C) 2004 David Gibson, IBM Corporation
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*/
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#ifndef _POWERPC_PMC_H
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#define _POWERPC_PMC_H
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#ifdef __KERNEL__
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#include <asm/ptrace.h>
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typedef void (*perf_irq_t)(struct pt_regs *);
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extern perf_irq_t perf_irq;
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int reserve_pmc_hardware(perf_irq_t new_perf_irq);
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void release_pmc_hardware(void);
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void ppc_enable_pmcs(void);
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#ifdef CONFIG_PPC_BOOK3S_64
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#include <asm/lppaca.h>
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#include <asm/firmware.h>
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static inline void ppc_set_pmu_inuse(int inuse)
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{
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#if defined(CONFIG_PPC_PSERIES) || defined(CONFIG_KVM_BOOK3S_HV_POSSIBLE)
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if (firmware_has_feature(FW_FEATURE_LPAR)) {
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#ifdef CONFIG_PPC_PSERIES
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get_lppaca()->pmcregs_in_use = inuse;
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#endif
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}
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#ifdef CONFIG_KVM_BOOK3S_HV_POSSIBLE
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get_paca()->pmcregs_in_use = inuse;
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#endif
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#endif
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}
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#ifdef CONFIG_KVM_BOOK3S_HV_POSSIBLE
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static inline int ppc_get_pmu_inuse(void)
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{
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return get_paca()->pmcregs_in_use;
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}
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#endif
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extern void power4_enable_pmcs(void);
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#else /* CONFIG_PPC64 */
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static inline void ppc_set_pmu_inuse(int inuse) { }
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#endif
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#endif /* __KERNEL__ */
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#endif /* _POWERPC_PMC_H */
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