qemu/accel/stubs/kvm-stub.c
David Gibson aacdb84413 sev: Remove false abstraction of flash encryption
When AMD's SEV memory encryption is in use, flash memory banks (which are
initialed by pc_system_flash_map()) need to be encrypted with the guest's
key, so that the guest can read them.

That's abstracted via the kvm_memcrypt_encrypt_data() callback in the KVM
state.. except, that it doesn't really abstract much at all.

For starters, the only call site is in code specific to the 'pc'
family of machine types, so it's obviously specific to those and to
x86 to begin with.  But it makes a bunch of further assumptions that
need not be true about an arbitrary confidential guest system based on
memory encryption, let alone one based on other mechanisms:

 * it assumes that the flash memory is defined to be encrypted with the
   guest key, rather than being shared with hypervisor
 * it assumes that that hypervisor has some mechanism to encrypt data into
   the guest, even though it can't decrypt it out, since that's the whole
   point
 * the interface assumes that this encrypt can be done in place, which
   implies that the hypervisor can write into a confidential guests's
   memory, even if what it writes isn't meaningful

So really, this "abstraction" is actually pretty specific to the way SEV
works.  So, this patch removes it and instead has the PC flash
initialization code call into a SEV specific callback.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
2021-02-08 16:57:38 +11:00

152 lines
2.6 KiB
C

/*
* QEMU KVM stub
*
* Copyright Red Hat, Inc. 2010
*
* Author: Paolo Bonzini <pbonzini@redhat.com>
*
* This work is licensed under the terms of the GNU GPL, version 2 or later.
* See the COPYING file in the top-level directory.
*
*/
#include "qemu/osdep.h"
#include "cpu.h"
#include "sysemu/kvm.h"
#ifndef CONFIG_USER_ONLY
#include "hw/pci/msi.h"
#endif
KVMState *kvm_state;
bool kvm_kernel_irqchip;
bool kvm_async_interrupts_allowed;
bool kvm_eventfds_allowed;
bool kvm_irqfds_allowed;
bool kvm_resamplefds_allowed;
bool kvm_msi_via_irqfd_allowed;
bool kvm_gsi_routing_allowed;
bool kvm_gsi_direct_mapping;
bool kvm_allowed;
bool kvm_readonly_mem_allowed;
bool kvm_ioeventfd_any_length_allowed;
bool kvm_msi_use_devid;
void kvm_flush_coalesced_mmio_buffer(void)
{
}
void kvm_cpu_synchronize_state(CPUState *cpu)
{
}
bool kvm_has_sync_mmu(void)
{
return false;
}
int kvm_has_many_ioeventfds(void)
{
return 0;
}
int kvm_update_guest_debug(CPUState *cpu, unsigned long reinject_trap)
{
return -ENOSYS;
}
int kvm_insert_breakpoint(CPUState *cpu, target_ulong addr,
target_ulong len, int type)
{
return -EINVAL;
}
int kvm_remove_breakpoint(CPUState *cpu, target_ulong addr,
target_ulong len, int type)
{
return -EINVAL;
}
void kvm_remove_all_breakpoints(CPUState *cpu)
{
}
int kvm_on_sigbus_vcpu(CPUState *cpu, int code, void *addr)
{
return 1;
}
int kvm_on_sigbus(int code, void *addr)
{
return 1;
}
#ifndef CONFIG_USER_ONLY
int kvm_irqchip_add_msi_route(KVMState *s, int vector, PCIDevice *dev)
{
return -ENOSYS;
}
void kvm_init_irq_routing(KVMState *s)
{
}
void kvm_irqchip_release_virq(KVMState *s, int virq)
{
}
int kvm_irqchip_update_msi_route(KVMState *s, int virq, MSIMessage msg,
PCIDevice *dev)
{
return -ENOSYS;
}
void kvm_irqchip_commit_routes(KVMState *s)
{
}
void kvm_irqchip_add_change_notifier(Notifier *n)
{
}
void kvm_irqchip_remove_change_notifier(Notifier *n)
{
}
void kvm_irqchip_change_notify(void)
{
}
int kvm_irqchip_add_adapter_route(KVMState *s, AdapterInfo *adapter)
{
return -ENOSYS;
}
int kvm_irqchip_add_irqfd_notifier_gsi(KVMState *s, EventNotifier *n,
EventNotifier *rn, int virq)
{
return -ENOSYS;
}
int kvm_irqchip_remove_irqfd_notifier_gsi(KVMState *s, EventNotifier *n,
int virq)
{
return -ENOSYS;
}
bool kvm_has_free_slot(MachineState *ms)
{
return false;
}
void kvm_init_cpu_signals(CPUState *cpu)
{
abort();
}
bool kvm_arm_supports_user_irq(void)
{
return false;
}
#endif