[PATCH v6 30/60] i386/tdx: Wire TDX_REPORT_FATAL_ERROR with GuestPanic facility

Xiaoyao Li
2024-11-05T06:38:31Z

Integrate TDX's TDX_REPORT_FATAL_ERROR into QEMU GuestPanic facility

Originated-from: Isaku Yamahata <isaku.yamahata@intel.com>
Signed-off-by: Xiaoyao Li <xiaoyao.li@intel.com>
---
Changes in v6:
- change error_code of GuestPanicInformationTdx from uint64_t to
uint32_t, to only contains the bit 31:0 returned in r12.

Changes in v5:
- mention additional error information in gpa when it presents;
- refine the documentation; (Markus)

Changes in v4:
- refine the documentation; (Markus)

Changes in v3:
- Add docmentation of new type and struct; (Daniel)
- refine the error message handling; (Daniel)
---
qapi/run-state.json | 31 +++++++++++++++++++++--
system/runstate.c | 58 +++++++++++++++++++++++++++++++++++++++++++
target/i386/kvm/tdx.c | 24 +++++++++++++++++-
3 files changed, 110 insertions(+), 3 deletions(-)

diff --git a/qapi/run-state.json b/qapi/run-state.json
index ce95cfa46b73..c5b0b747b30d 100644
--- a/qapi/run-state.json
+++ b/qapi/run-state.json
@@ -501,10 +501,12 @@
#
# @s390: s390 guest panic information type (Since: 2.12)
#
+# @tdx: tdx guest panic information type (Since: 9.0)
+#
# Since: 2.9
##
{ 'enum': 'GuestPanicInformationType',
- 'data': [ 'hyper-v', 's390' ] }
+ 'data': [ 'hyper-v', 's390', 'tdx' ] }

##
# @GuestPanicInformation:
@@ -519,7 +521,8 @@
'base': {'type': 'GuestPanicInformationType'},
'discriminator': 'type',
'data': {'hyper-v': 'GuestPanicInformationHyperV',
- 's390': 'GuestPanicInformationS390'}}
+ 's390': 'GuestPanicInformationS390',
+ 'tdx' : 'GuestPanicInformationTdx'}}

##
# @GuestPanicInformationHyperV:
@@ -598,6 +601,30 @@
'psw-addr': 'uint64',
'reason': 'S390CrashReason'}}

+##
+# @GuestPanicInformationTdx:
+#
+# TDX Guest panic information specific to TDX, as specified in the
+# "Guest-Hypervisor Communication Interface (GHCI) Specification",
+# section TDG.VP.VMCALL<ReportFatalError>.
+#
+# @error-code: TD-specific error code
+#
+# @message: Human-readable error message provided by the guest. Not
+# to be trusted.
+#
+# @gpa: guest-physical address of a page that contains more verbose
+# error information, as zero-terminated string. Present when the
+# "GPA valid" bit (bit 63) is set in @error-code.
+#
+#
+# Since: 9.0
+##
+{'struct': 'GuestPanicInformationTdx',
+ 'data': {'error-code': 'uint32',
+ 'message': 'str',
+ '*gpa': 'uint64'}}
+
##
# @MEMORY_FAILURE:
#
diff --git a/system/runstate.c b/system/runstate.c
index c2c9afa905a6..9bb8162eb28f 100644
--- a/system/runstate.c
+++ b/system/runstate.c
@@ -565,6 +565,52 @@ static void qemu_system_wakeup(void)
}
}

+static char *tdx_parse_panic_message(char *message)
+{
+ bool printable = false;
+ char *buf = NULL;
+ int len = 0, i;
+
+ /*
+ * Although message is defined as a json string, we shouldn't
+ * unconditionally treat it as is because the guest generated it and
+ * it's not necessarily trustable.
+ */
+ if (message) {
+ /* The caller guarantees the NUL-terminated string. */
+ len = strlen(message);
+
+ printable = len > 0;
+ for (i = 0; i < len; i++) {
+ if (!(0x20 <= message[i] && message[i] <= 0x7e)) {
+ printable = false;
+ break;
+ }
+ }
+ }
+
+ if (!printable && len) {
+ /* 3 = length of "%02x " */
+ buf = g_malloc(len * 3);
+ for (i = 0; i < len; i++) {
+ if (message[i] == '\0') {
+ break;
+ } else {
+ sprintf(buf + 3 * i, "%02x ", message[i]);
+ }
+ }
+ if (i > 0)
+ /* replace the last ' '(space) to NUL */
+ buf[i * 3 - 1] = '\0';
+ else
+ buf[0] = '\0';
+
+ return buf;
+ }
+
+ return message;
+}
+
void qemu_system_guest_panicked(GuestPanicInformation *info)
{
qemu_log_mask(LOG_GUEST_ERROR, "Guest crashed");
@@ -606,7 +652,19 @@ void qemu_system_guest_panicked(GuestPanicInformation *info)
S390CrashReason_str(info->u.s390.reason),
info->u.s390.psw_mask,
info->u.s390.psw_addr);
+ } else if (info->type == GUEST_PANIC_INFORMATION_TYPE_TDX) {
+ qemu_log_mask(LOG_GUEST_ERROR,
+ "\nTDX guest reports fatal error:"
+ " error code: 0x%" PRIx32 " error message:\"%s\"\n",
+ info->u.tdx.error_code,
+ tdx_parse_panic_message(info->u.tdx.message));
+ if (info->u.tdx.gpa != -1ull) {
+ qemu_log_mask(LOG_GUEST_ERROR, "Additional error information "
+ "can be found at gpa page: 0x%" PRIx64 "\n",
+ info->u.tdx.gpa);
+ }
}
+
qapi_free_GuestPanicInformation(info);
}
}
diff --git a/target/i386/kvm/tdx.c b/target/i386/kvm/tdx.c
index 3f44dfbf6585..394f1d75dc0d 100644
--- a/target/i386/kvm/tdx.c
+++ b/target/i386/kvm/tdx.c
@@ -17,6 +17,7 @@
#include "qemu/mmap-alloc.h"
#include "qapi/error.h"
#include "qom/object_interfaces.h"
+#include "sysemu/runstate.h"
#include "sysemu/sysemu.h"
#include "exec/ramblock.h"

@@ -574,10 +575,25 @@ int tdx_parse_tdvf(void *flash_ptr, int size)
return tdvf_parse_metadata(&tdx_guest->tdvf, flash_ptr, size);
}

+static void tdx_panicked_on_fatal_error(X86CPU *cpu, uint64_t error_code,
+ char *message, uint64_t gpa)
+{
+ GuestPanicInformation *panic_info;
+
+ panic_info = g_new0(GuestPanicInformation, 1);
+ panic_info->type = GUEST_PANIC_INFORMATION_TYPE_TDX;
+ panic_info->u.tdx.error_code = (uint32_t) error_code;
+ panic_info->u.tdx.message = message;
+ panic_info->u.tdx.gpa = gpa;
+
+ qemu_system_guest_panicked(panic_info);
+}
+
int tdx_handle_report_fatal_error(X86CPU *cpu, struct kvm_run *run)
{
uint64_t error_code = run->system_event.data[0];
char *message = NULL;
+ uint64_t gpa = -1ull;

if (error_code & 0xffff) {
error_report("TDX: REPORT_FATAL_ERROR: invalid error code: 0x%lx",
@@ -594,7 +610,13 @@ int tdx_handle_report_fatal_error(X86CPU *cpu, struct kvm_run *run)
message[TDX_FATAL_MESSAGE_MAX] = '\0';
}

- error_report("TD guest reports fatal error. %s", message ? : "");
+#define TDX_REPORT_FATAL_ERROR_GPA_VALID BIT_ULL(63)
+ if (error_code & TDX_REPORT_FATAL_ERROR_GPA_VALID) {
+ gpa = run->system_event.data[1];
+ }
+
+ tdx_panicked_on_fatal_error(cpu, error_code, message, gpa);
+
return -1;
}

--
2.34.1