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68 lines
2.6 KiB
68 lines
2.6 KiB
1 month ago
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From 4c93bec108f7e3918a2ef91b51cec477ade38cc3 Mon Sep 17 00:00:00 2001
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From: Paolo Bonzini <pbonzini@redhat.com>
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Date: Mon, 18 Mar 2024 17:45:56 -0400
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Subject: [PATCH 018/100] runstate: skip initial CPU reset if reset is not
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actually possible
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MIME-Version: 1.0
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Content-Type: text/plain; charset=UTF-8
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Content-Transfer-Encoding: 8bit
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RH-Author: Paolo Bonzini <pbonzini@redhat.com>
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RH-MergeRequest: 245: SEV-SNP support
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RH-Jira: RHEL-39544
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RH-Acked-by: Thomas Huth <thuth@redhat.com>
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RH-Acked-by: Bandan Das <bdas@redhat.com>
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RH-Acked-by: Vitaly Kuznetsov <vkuznets@redhat.com>
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RH-Commit: [18/91] ced267fdaadbf2072c1897223522457a006e6c81 (bonzini/rhel-qemu-kvm)
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Right now, the system reset is concluded by a call to
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cpu_synchronize_all_post_reset() in order to sync any changes
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that the machine reset callback applied to the CPU state.
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However, for VMs with encrypted state such as SEV-ES guests (currently
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the only case of guests with non-resettable CPUs) this cannot be done,
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because guest state has already been finalized by machine-init-done notifiers.
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cpu_synchronize_all_post_reset() does nothing on these guests, and actually
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we would like to make it fail if called once guest has been encrypted.
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So, assume that boards that support non-resettable CPUs do not touch
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CPU state and that all such setup is done before, at the time of
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cpu_synchronize_all_post_init().
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Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
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Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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(cherry picked from commit 08b2d15cdd0d3fbbe37ce23bf192b770db3a7539)
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Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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---
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system/runstate.c | 15 ++++++++++++++-
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1 file changed, 14 insertions(+), 1 deletion(-)
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diff --git a/system/runstate.c b/system/runstate.c
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index d6ab860eca..cb4905a40f 100644
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--- a/system/runstate.c
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+++ b/system/runstate.c
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@@ -501,7 +501,20 @@ void qemu_system_reset(ShutdownCause reason)
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default:
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qapi_event_send_reset(shutdown_caused_by_guest(reason), reason);
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}
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- cpu_synchronize_all_post_reset();
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+
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+ /*
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+ * Some boards use the machine reset callback to point CPUs to the firmware
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+ * entry point. Assume that this is not the case for boards that support
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+ * non-resettable CPUs (currently used only for confidential guests), in
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+ * which case cpu_synchronize_all_post_init() is enough because
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+ * it does _more_ than cpu_synchronize_all_post_reset().
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+ */
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+ if (cpus_are_resettable()) {
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+ cpu_synchronize_all_post_reset();
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+ } else {
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+ assert(runstate_check(RUN_STATE_PRELAUNCH));
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+ }
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+
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vm_set_suspended(false);
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}
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--
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2.39.3
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