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28d2a6e668
The ability to run nested guests under KVM means that a guest can also
act as a hypervisor for it's own nested guest. Currently
ppc_set_pmu_inuse() assumes that either FW_FEATURE_LPAR is set,
indicating a guest environment, and so sets the pmcregs_in_use flag in
the lppaca, or that it isn't set, indicating a hypervisor environment,
and so sets the pmcregs_in_use flag in the paca.
The pmcregs_in_use flag in the lppaca is used to communicate this
information to a hypervisor and so must be set in a guest environment.
The pmcregs_in_use flag in the paca is used by KVM code to determine
whether the host state of the performance monitoring unit (PMU) must
be saved and restored when running a guest.
Thus when a guest also acts as a hypervisor it must set this bit in
both places since it needs to ensure both that the real hypervisor
saves it's PMU registers when it runs (requires pmcregs_in_use flag in
lppaca), and that it saves it's own PMU registers when running a
nested guest (requires pmcregs_in_use flag in paca).
Modify ppc_set_pmu_inuse() so that the pmcregs_in_use bit is set in
both the lppaca and the paca when a guest (LPAR) is running with the
capability of running it's own guests (CONFIG_KVM_BOOK3S_HV_POSSIBLE).
Fixes: 95a6432ce9 ("KVM: PPC: Book3S HV: Streamlined guest entry/exit path on P9 for radix guests")
Cc: stable@vger.kernel.org # v4.20+
Signed-off-by: Suraj Jitindar Singh <sjitindarsingh@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20190703012022.15644-2-sjitindarsingh@gmail.com
47 lines
989 B
C
47 lines
989 B
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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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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