From: Tom Lendacky <thomas.lenda...@amd.com>
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.mayd...@linaro.org>
Cc: Aurelien Jarno <aurel...@aurel32.net>
Cc: Jiaxun Yang <jiaxun.y...@flygoat.com>
Cc: Aleksandar Rikalo <aleksandar.rik...@syrmia.com>
Cc: David Gibson <da...@gibson.dropbear.id.au>
Cc: David Hildenbrand <da...@redhat.com>
Signed-off-by: Tom Lendacky <thomas.lenda...@amd.com>
---
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 | 7 +++++--
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, 58 insertions(+), 2 deletions(-)
diff --git a/accel/kvm/kvm-all.c b/accel/kvm/kvm-all.c
index 9db74b465e..9ac44ad018 100644
--- a/accel/kvm/kvm-all.c
+++ b/accel/kvm/kvm-all.c
@@ -2411,6 +2411,11 @@ 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 636aab0add..7b4f212d19 100644
--- a/softmmu/runstate.c
+++ b/softmmu/runstate.c
@@ -523,8 +523,11 @@ void qemu_system_guest_crashloaded(GuestPanicInformation
*info)
void qemu_system_reset_request(ShutdownCause reason)
{
- if (reboot_action == REBOOT_ACTION_SHUTDOWN &&
- reason != SHUTDOWN_CAUSE_SUBSYSTEM_RESET) {
+ if (!cpus_are_resettable()) {
+ error_report("cpus are not resettable, terminating");
+ shutdown_requested = reason;
+ } else if (reboot_action == REBOOT_ACTION_SHUTDOWN &&
+ reason != SHUTDOWN_CAUSE_SUBSYSTEM_RESET) {
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 477692566a..a907c59c5e 100644
--- a/target/mips/kvm.c
+++ b/target/mips/kvm.c
@@ -1289,3 +1289,8 @@ 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 b8385e6b95..5c5ba801f1 100644
--- a/target/s390x/kvm.c
+++ b/target/s390x/kvm.c
@@ -2601,3 +2601,8 @@ 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
