sev/i386: Don't allow a system reset under an SEV-ES guest

An SEV-ES guest does not allow register state to be altered once it has
been measured. When an SEV-ES guest issues a reboot command, Qemu will
reset the vCPU state and resume the guest. This will cause failures under
SEV-ES. Prevent that from occuring by introducing an arch-specific
callback that returns a boolean indicating whether vCPUs are resettable.

Cc: Peter Maydell <peter.maydell@linaro.org>
Cc: Aurelien Jarno <aurelien@aurel32.net>
Cc: Jiaxun Yang <jiaxun.yang@flygoat.com>
Cc: Aleksandar Rikalo <aleksandar.rikalo@syrmia.com>
Cc: David Gibson <david@gibson.dropbear.id.au>
Cc: David Hildenbrand <david@redhat.com>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
Reviewed-by: Venu Busireddy <venu.busireddy@oracle.com>
Message-Id: <1ac39c441b9a3e970e9556e1cc29d0a0814de6fd.1611682609.git.thomas.lendacky@amd.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Tom Lendacky 2021-01-26 11:36:47 -06:00 committed by Paolo Bonzini
parent b2f73a0784
commit 92a5199b29
11 changed files with 56 additions and 0 deletions

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@ -2312,6 +2312,11 @@ void kvm_flush_coalesced_mmio_buffer(void)
s->coalesced_flush_in_progress = false;
}
bool kvm_cpu_check_are_resettable(void)
{
return kvm_arch_cpu_check_are_resettable();
}
static void do_kvm_cpu_synchronize_state(CPUState *cpu, run_on_cpu_data arg)
{
if (!cpu->vcpu_dirty) {

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@ -41,6 +41,8 @@ extern int icount_align_option;
/* Unblock cpu */
void qemu_cpu_kick_self(void);
bool cpus_are_resettable(void);
void cpu_synchronize_all_states(void);
void cpu_synchronize_all_post_reset(void);
void cpu_synchronize_all_post_init(void);

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@ -22,4 +22,9 @@ void cpu_synchronize_post_reset(CPUState *cpu);
void cpu_synchronize_post_init(CPUState *cpu);
void cpu_synchronize_pre_loadvm(CPUState *cpu);
static inline bool cpu_check_are_resettable(void)
{
return kvm_enabled() ? kvm_cpu_check_are_resettable() : true;
}
#endif /* QEMU_HW_ACCEL_H */

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@ -541,4 +541,14 @@ int kvm_get_max_memslots(void);
/* Notify resamplefd for EOI of specific interrupts. */
void kvm_resample_fd_notify(int gsi);
/**
* kvm_cpu_check_are_resettable - return whether CPUs can be reset
*
* Returns: true: CPUs are resettable
* false: CPUs are not resettable
*/
bool kvm_cpu_check_are_resettable(void);
bool kvm_arch_cpu_check_are_resettable(void);
#endif

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@ -194,6 +194,11 @@ void cpu_synchronize_pre_loadvm(CPUState *cpu)
}
}
bool cpus_are_resettable(void)
{
return cpu_check_are_resettable();
}
int64_t cpus_get_virtual_clock(void)
{
/*

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@ -528,6 +528,9 @@ void qemu_system_reset_request(ShutdownCause reason)
if (reboot_action == REBOOT_ACTION_SHUTDOWN &&
reason != SHUTDOWN_CAUSE_SUBSYSTEM_RESET) {
shutdown_requested = reason;
} else if (!cpus_are_resettable()) {
error_report("cpus are not resettable, terminating");
shutdown_requested = reason;
} else {
reset_requested = reason;
}

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@ -1045,3 +1045,8 @@ int kvm_arch_msi_data_to_gsi(uint32_t data)
{
return (data - 32) & 0xffff;
}
bool kvm_arch_cpu_check_are_resettable(void)
{
return true;
}

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@ -27,6 +27,7 @@
#include "sysemu/kvm_int.h"
#include "sysemu/runstate.h"
#include "kvm_i386.h"
#include "sev_i386.h"
#include "hyperv.h"
#include "hyperv-proto.h"
@ -4821,3 +4822,8 @@ bool kvm_has_waitpkg(void)
{
return has_msr_umwait;
}
bool kvm_arch_cpu_check_are_resettable(void)
{
return !sev_es_enabled();
}

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@ -1290,3 +1290,8 @@ int mips_kvm_type(MachineState *machine, const char *vm_type)
return -1;
}
bool kvm_arch_cpu_check_are_resettable(void)
{
return true;
}

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@ -2929,3 +2929,8 @@ void kvmppc_set_reg_tb_offset(PowerPCCPU *cpu, int64_t tb_offset)
kvm_set_one_reg(cs, KVM_REG_PPC_TB_OFFSET, &tb_offset);
}
}
bool kvm_arch_cpu_check_are_resettable(void)
{
return true;
}

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@ -2599,3 +2599,8 @@ void kvm_s390_stop_interrupt(S390CPU *cpu)
kvm_s390_vcpu_interrupt(cpu, &irq);
}
bool kvm_arch_cpu_check_are_resettable(void)
{
return true;
}