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107c55005f
KVM guests have certain restrictions and performance quirks when using doorbells. This patch moves the EPAPR KVM guest test so it can be shared with PSERIES, and uses that in doorbell setup code to apply the KVM guest quirks and improves IPI performance for two cases: - PowerVM guests may now use doorbells even if they are secure. - KVM guests no longer use doorbells if XIVE is available. There is a valid complaint that "KVM guest" is not a very reasonable thing to test for, it's preferable for the hypervisor to advertise particular behaviours to the guest so they could change if the hypervisor implementation or configuration changes. However in this case we were already assuming a KVM guest worst case, so this patch is about containing those quirks. If KVM later advertises fast doorbells, we should test for that and override the quirks. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Tested-by: Cédric Le Goater <clg@kaod.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20200726035155.1424103-4-npiggin@gmail.com
37 lines
832 B
C
37 lines
832 B
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/*
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* Extracted from cputable.c
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*
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* Copyright (C) 2001 Ben. Herrenschmidt (benh@kernel.crashing.org)
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*
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* Modifications for ppc64:
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* Copyright (C) 2003 Dave Engebretsen <engebret@us.ibm.com>
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* Copyright (C) 2005 Stephen Rothwell, IBM Corporation
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*/
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#include <linux/export.h>
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#include <linux/cache.h>
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#include <linux/of.h>
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#include <asm/firmware.h>
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#ifdef CONFIG_PPC64
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unsigned long powerpc_firmware_features __read_mostly;
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EXPORT_SYMBOL_GPL(powerpc_firmware_features);
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#endif
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#if defined(CONFIG_PPC_PSERIES) || defined(CONFIG_KVM_GUEST)
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bool is_kvm_guest(void)
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{
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struct device_node *hyper_node;
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hyper_node = of_find_node_by_path("/hypervisor");
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if (!hyper_node)
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return 0;
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if (!of_device_is_compatible(hyper_node, "linux,kvm"))
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return 0;
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return 1;
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}
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#endif
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