xemu/target/i386/kvm_i386.h
David Woodhouse c1bb5418e3 target/i386: Support up to 32768 CPUs without IRQ remapping
The IOAPIC has an 'Extended Destination ID' field in its RTE, which maps
to bits 11-4 of the MSI address. Since those address bits fall within a
given 4KiB page they were historically non-trivial to use on real hardware.

The Intel IOMMU uses the lowest bit to indicate a remappable format MSI,
and then the remaining 7 bits are part of the index.

Where the remappable format bit isn't set, we can actually use the other
seven to allow external (IOAPIC and MSI) interrupts to reach up to 32768
CPUs instead of just the 255 permitted on bare metal.

Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Message-Id: <78097f9218300e63e751e077a0a5ca029b56ba46.camel@infradead.org>
[Fix UBSAN warning. - Paolo]
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

Signed-off-by: David Woodhouse <dwmw2@infradead.org>
2020-12-10 12:15:00 -05:00

54 lines
1.2 KiB
C

/*
* QEMU KVM support -- x86 specific functions.
*
* Copyright (c) 2012 Linaro Limited
*
* This work is licensed under the terms of the GNU GPL, version 2 or later.
* See the COPYING file in the top-level directory.
*
*/
#ifndef QEMU_KVM_I386_H
#define QEMU_KVM_I386_H
#include "sysemu/kvm.h"
#define kvm_apic_in_kernel() (kvm_irqchip_in_kernel())
#ifdef CONFIG_KVM
#define kvm_pit_in_kernel() \
(kvm_irqchip_in_kernel() && !kvm_irqchip_is_split())
#define kvm_pic_in_kernel() \
(kvm_irqchip_in_kernel() && !kvm_irqchip_is_split())
#define kvm_ioapic_in_kernel() \
(kvm_irqchip_in_kernel() && !kvm_irqchip_is_split())
#else
#define kvm_pit_in_kernel() 0
#define kvm_pic_in_kernel() 0
#define kvm_ioapic_in_kernel() 0
#endif /* CONFIG_KVM */
bool kvm_has_smm(void);
bool kvm_has_adjust_clock(void);
bool kvm_has_adjust_clock_stable(void);
bool kvm_has_exception_payload(void);
void kvm_synchronize_all_tsc(void);
void kvm_arch_reset_vcpu(X86CPU *cs);
void kvm_arch_do_init_vcpu(X86CPU *cs);
void kvm_put_apicbase(X86CPU *cpu, uint64_t value);
bool kvm_enable_x2apic(void);
bool kvm_has_x2apic_api(void);
bool kvm_has_waitpkg(void);
bool kvm_hv_vpindex_settable(void);
uint64_t kvm_swizzle_msi_ext_dest_id(uint64_t address);
#endif