On 2021-01-26 11:36:47 -0600, Tom Lendacky wrote:
> From: Tom Lendacky <thomas.lendacky@xxxxxxx>
>
> 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@xxxxxxxxxx>
> Cc: Aurelien Jarno <aurelien@xxxxxxxxxxx>
> Cc: Jiaxun Yang <jiaxun.yang@xxxxxxxxxxx>
> Cc: Aleksandar Rikalo <aleksandar.rikalo@xxxxxxxxxx>
> Cc: David Gibson <david@xxxxxxxxxxxxxxxxxxxxx>
> Cc: David Hildenbrand <david@xxxxxxxxxx>
> Reviewed-by: Dr. David Alan Gilbert <dgilbert@xxxxxxxxxx>
> Signed-off-by: Tom Lendacky <thomas.lendacky@xxxxxxx>
Reviewed-by: Venu Busireddy <venu.busireddy@xxxxxxxxxx>
> ---
> accel/kvm/kvm-all.c | 5 +++++
> include/sysemu/cpus.h | 2 ++
> include/sysemu/hw_accel.h | 5 +++++
> include/sysemu/kvm.h | 10 ++++++++++
> softmmu/cpus.c | 5 +++++
> softmmu/runstate.c | 3 +++
> target/arm/kvm.c | 5 +++++
> target/i386/kvm/kvm.c | 6 ++++++
> target/mips/kvm.c | 5 +++++
> target/ppc/kvm.c | 5 +++++
> target/s390x/kvm.c | 5 +++++
> 11 files changed, 56 insertions(+)
>
> diff --git a/accel/kvm/kvm-all.c b/accel/kvm/kvm-all.c
> index 410879cf94..6c099a3869 100644
> --- a/accel/kvm/kvm-all.c
> +++ b/accel/kvm/kvm-all.c
> @@ -2414,6 +2414,11 @@ 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) {
> diff --git a/include/sysemu/cpus.h b/include/sysemu/cpus.h
> index e8156728c6..1cb4f9dbeb 100644
> --- a/include/sysemu/cpus.h
> +++ b/include/sysemu/cpus.h
> @@ -57,6 +57,8 @@ 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);
> diff --git a/include/sysemu/hw_accel.h b/include/sysemu/hw_accel.h
> index ffed6192a3..61672f9b32 100644
> --- a/include/sysemu/hw_accel.h
> +++ b/include/sysemu/hw_accel.h
> @@ -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 */
> diff --git a/include/sysemu/kvm.h b/include/sysemu/kvm.h
> index 875ca101e3..3e265cea3d 100644
> --- a/include/sysemu/kvm.h
> +++ b/include/sysemu/kvm.h
> @@ -573,4 +573,14 @@ 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
> diff --git a/softmmu/cpus.c b/softmmu/cpus.c
> index 1dc20b9dc3..89de46eae0 100644
> --- a/softmmu/cpus.c
> +++ b/softmmu/cpus.c
> @@ -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)
> {
> /*
> diff --git a/softmmu/runstate.c b/softmmu/runstate.c
> index beee050815..1813691898 100644
> --- a/softmmu/runstate.c
> +++ b/softmmu/runstate.c
> @@ -527,6 +527,9 @@ 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;
> }
> diff --git a/target/arm/kvm.c b/target/arm/kvm.c
> index ffe186de8d..00e124c812 100644
> --- a/target/arm/kvm.c
> +++ b/target/arm/kvm.c
> @@ -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;
> +}
> diff --git a/target/i386/kvm/kvm.c b/target/i386/kvm/kvm.c
> index aaae79557d..bb6bfc19de 100644
> --- a/target/i386/kvm/kvm.c
> +++ b/target/i386/kvm/kvm.c
> @@ -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"
>
> @@ -4788,3 +4789,8 @@ bool kvm_has_waitpkg(void)
> {
> return has_msr_umwait;
> }
> +
> +bool kvm_arch_cpu_check_are_resettable(void)
> +{
> + return !sev_es_enabled();
> +}
> diff --git a/target/mips/kvm.c b/target/mips/kvm.c
> index 84fb10ea35..123ec1be7e 100644
> --- a/target/mips/kvm.c
> +++ b/target/mips/kvm.c
> @@ -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;
> +}
> diff --git a/target/ppc/kvm.c b/target/ppc/kvm.c
> index daf690a678..f45ed11058 100644
> --- a/target/ppc/kvm.c
> +++ b/target/ppc/kvm.c
> @@ -2947,3 +2947,8 @@ void kvmppc_svm_off(Error **errp)
> error_setg_errno(errp, -rc, "KVM_PPC_SVM_OFF ioctl failed");
> }
> }
> +
> +bool kvm_arch_cpu_check_are_resettable(void)
> +{
> + return true;
> +}
> diff --git a/target/s390x/kvm.c b/target/s390x/kvm.c
> index dc27fa36c9..7a892d663d 100644
> --- a/target/s390x/kvm.c
> +++ b/target/s390x/kvm.c
> @@ -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;
> +}
> --
> 2.30.0
>
