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67730e6c53
Use the kernel's canonical $(ARCH) paths instead of the raw target triple for KVM selftests directories. KVM selftests are quite nearly the only place in the entire kernel that using the target triple for directories, tools/testing/selftests/drivers/s390x being the lone holdout. Using the kernel's preferred nomenclature eliminates the minor, but annoying, friction of having to translate to KVM's selftests directories, e.g. for pattern matching, opening files, running selftests, etc. Opportunsitically delete file comments that reference the full path of the file, as they are obviously prone to becoming stale, and serve no known purpose. Reviewed-by: Muhammad Usama Anjum <usama.anjum@collabora.com> Acked-by: Claudio Imbrenda <imbrenda@linux.ibm.com> Acked-by: Andrew Jones <ajones@ventanamicro.com> Link: https://lore.kernel.org/r/20241128005547.4077116-16-seanjc@google.com Signed-off-by: Sean Christopherson <seanjc@google.com>
56 lines
1.5 KiB
C
56 lines
1.5 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* ucall support. A ucall is a "hypercall to userspace".
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*
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* Copyright (C) 2018, Red Hat, Inc.
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*/
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#include "kvm_util.h"
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#define UCALL_PIO_PORT ((uint16_t)0x1000)
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void ucall_arch_do_ucall(vm_vaddr_t uc)
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{
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/*
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* FIXME: Revert this hack (the entire commit that added it) once nVMX
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* preserves L2 GPRs across a nested VM-Exit. If a ucall from L2, e.g.
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* to do a GUEST_SYNC(), lands the vCPU in L1, any and all GPRs can be
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* clobbered by L1. Save and restore non-volatile GPRs (clobbering RBP
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* in particular is problematic) along with RDX and RDI (which are
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* inputs), and clobber volatile GPRs. *sigh*
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*/
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#define HORRIFIC_L2_UCALL_CLOBBER_HACK \
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"rcx", "rsi", "r8", "r9", "r10", "r11"
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asm volatile("push %%rbp\n\t"
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"push %%r15\n\t"
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"push %%r14\n\t"
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"push %%r13\n\t"
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"push %%r12\n\t"
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"push %%rbx\n\t"
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"push %%rdx\n\t"
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"push %%rdi\n\t"
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"in %[port], %%al\n\t"
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"pop %%rdi\n\t"
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"pop %%rdx\n\t"
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"pop %%rbx\n\t"
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"pop %%r12\n\t"
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"pop %%r13\n\t"
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"pop %%r14\n\t"
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"pop %%r15\n\t"
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"pop %%rbp\n\t"
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: : [port] "d" (UCALL_PIO_PORT), "D" (uc) : "rax", "memory",
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HORRIFIC_L2_UCALL_CLOBBER_HACK);
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}
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void *ucall_arch_get_ucall(struct kvm_vcpu *vcpu)
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{
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struct kvm_run *run = vcpu->run;
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if (run->exit_reason == KVM_EXIT_IO && run->io.port == UCALL_PIO_PORT) {
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struct kvm_regs regs;
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vcpu_regs_get(vcpu, ®s);
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return (void *)regs.rdi;
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}
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return NULL;
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}
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