[xen staging] vtpmmgr: Shutdown more gracefully

[patchbot@xxxxxxx]

commit 1b4bfa0b8f6a47c2b80bdc203bb0487fe1bd4366
Author:     Jason Andryuk <jandryuk@xxxxxxxxx>
AuthorDate: Thu May 6 09:59:18 2021 -0400
Commit:     Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
CommitDate: Mon May 10 14:49:01 2021 +0100

    vtpmmgr: Shutdown more gracefully
    
    vtpmmgr uses the default, weak app_shutdown, which immediately calls the
    shutdown hypercall.  This short circuits the vtpmmgr clean up logic.  We
    need to perform the clean up to actually Flush our key out of the tpm.
    
    Setting do_shutdown is one step in that direction, but vtpmmgr will most
    likely be waiting in tpmback_req_any.  We need to call shutdown_tpmback
    to cancel the wait inside tpmback and perform the shutdown.
    
    Signed-off-by: Jason Andryuk <jandryuk@xxxxxxxxx>
    Reviewed-by: Samuel Thibault <samuel.thibaut@xxxxxxxxxxxx>
    Reviewed-by: Daniel P. Smith <dpsmith@xxxxxxxxxxxxxxxxxxxx>
---
 stubdom/vtpmmgr/vtpmmgr.c | 12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)

diff --git a/stubdom/vtpmmgr/vtpmmgr.c b/stubdom/vtpmmgr/vtpmmgr.c
index 9fddaa24f8..46ea018921 100644
--- a/stubdom/vtpmmgr/vtpmmgr.c
+++ b/stubdom/vtpmmgr/vtpmmgr.c
@@ -67,11 +67,21 @@ int hw_is_tpm2(void)
     return (hardware_version.hw_version == TPM2_HARDWARE) ? 1 : 0;
 }
 
+static int do_shutdown;
+
+void app_shutdown(unsigned int reason)
+{
+    printk("Shutdown requested: %d\n", reason);
+    do_shutdown = 1;
+
+    shutdown_tpmback();
+}
+
 void main_loop(void) {
    tpmcmd_t* tpmcmd;
    uint8_t respbuf[TCPA_MAX_BUFFER_LENGTH];
 
-   while(1) {
+   while (!do_shutdown) {
       /* Wait for requests from a vtpm */
       vtpmloginfo(VTPM_LOG_VTPM, "Waiting for commands from vTPM's:\n");
       if((tpmcmd = tpmback_req_any()) == NULL) {
--
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