[PATCH v4 19/23] x86/acpi: disallow S3 on Secure Launch boot

Secure Launch won't initiate DRTM on S3 resume (the code for starting
DRTM is not part of Xen), so abort a request to perform S3 suspend to
not lose the state of DRTM PCRs.

Signed-off-by: Sergii Dmytruk <[email protected]>
---

Notes:
    v4: return EACCES instead of EPERM

 xen/arch/x86/acpi/power.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/xen/arch/x86/acpi/power.c b/xen/arch/x86/acpi/power.c
index 3452650a61..8428766f82 100644
--- a/xen/arch/x86/acpi/power.c
+++ b/xen/arch/x86/acpi/power.c
@@ -30,6 +30,7 @@
 #include <asm/microcode.h>
 #include <asm/mwait.h>
 #include <asm/prot-key.h>
+#include <asm/slaunch.h>
 #include <asm/spec_ctrl.h>
 #include <asm/tboot.h>
 #include <asm/trampoline.h>
@@ -335,6 +336,13 @@ int acpi_enter_sleep(const struct xenpf_enter_acpi_sleep *sleep)
            PAGE_SIZE - acpi_sinfo.vector_width / 8)) )
         return -EOPNOTSUPP;
 
+    /* Secure Launch won't initiate DRTM on S3 resume, so abort S3 suspend. */
+    if ( sleep->sleep_state == ACPI_STATE_S3 && slaunch_active )
+    {
+        printk(XENLOG_INFO "SLAUNCH: refusing switching into ACPI S3 state.\n");
+        return -EACCES;
+    }
+
     if ( sleep->flags & XENPF_ACPI_SLEEP_EXTENDED )
     {
         if ( !acpi_sinfo.sleep_control.address ||
-- 
2.55.0