x86/sev: Define the Linux-specific guest termination reasons

The GHCB specification defines the reason code for reason set 0. The
reason codes defined in the set 0 do not cover all possible causes for a
guest to request termination.

The reason sets 1 to 255 are reserved for the vendor-specific codes.
Reserve the reason set 1 for the Linux guest. Define the error codes for
reason set 1 so that one can have meaningful termination reasons and thus
better guest failure diagnosis.

While at it, change sev_es_terminate() to accept a reason set parameter.

  [ bp: Massage commit message. ]

Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Venu Busireddy <venu.busireddy@oracle.com>
Link: https://lore.kernel.org/r/20220307213356.2797205-11-brijesh.singh@amd.com

diff --git a/arch/x86/boot/compressed/sev.c b/arch/x86/boot/compressed/sev.c
index 27ccd5a..56e941d 100644 (file)
--- a/arch/x86/boot/compressed/sev.c
+++ b/arch/x86/boot/compressed/sev.c
@@ -119,7 +119,7 @@ static enum es_result vc_read_mem(struct es_em_ctxt *ctxt,
 static bool early_setup_sev_es(void)
 {
        if (!sev_es_negotiate_protocol())
-               sev_es_terminate(GHCB_SEV_ES_PROT_UNSUPPORTED);
+               sev_es_terminate(SEV_TERM_SET_GEN, GHCB_SEV_ES_PROT_UNSUPPORTED);
 
        if (set_page_decrypted((unsigned long)&boot_ghcb_page))
                return false;
@@ -172,7 +172,7 @@ void do_boot_stage2_vc(struct pt_regs *regs, unsigned long exit_code)
        enum es_result result;
 
        if (!boot_ghcb && !early_setup_sev_es())
-               sev_es_terminate(GHCB_SEV_ES_GEN_REQ);
+               sev_es_terminate(SEV_TERM_SET_GEN, GHCB_SEV_ES_GEN_REQ);
 
        vc_ghcb_invalidate(boot_ghcb);
        result = vc_init_em_ctxt(&ctxt, regs, exit_code);
@@ -199,7 +199,7 @@ finish:
        if (result == ES_OK)
                vc_finish_insn(&ctxt);
        else if (result != ES_RETRY)
-               sev_es_terminate(GHCB_SEV_ES_GEN_REQ);
+               sev_es_terminate(SEV_TERM_SET_GEN, GHCB_SEV_ES_GEN_REQ);
 }
 
 void sev_enable(struct boot_params *bp)

diff --git a/arch/x86/include/asm/sev-common.h b/arch/x86/include/asm/sev-common.h
index 1b2fd32..94f0ea5 100644 (file)
--- a/arch/x86/include/asm/sev-common.h
+++ b/arch/x86/include/asm/sev-common.h
@@ -73,9 +73,17 @@
         /* GHCBData[23:16] */                          \
        ((((u64)reason_val) & 0xff) << 16))
 
+/* Error codes from reason set 0 */
+#define SEV_TERM_SET_GEN               0
 #define GHCB_SEV_ES_GEN_REQ            0
 #define GHCB_SEV_ES_PROT_UNSUPPORTED   1
 
+/* Linux-specific reason codes (used with reason set 1) */
+#define SEV_TERM_SET_LINUX             1
+#define GHCB_TERM_REGISTER             0       /* GHCB GPA registration failure */
+#define GHCB_TERM_PSC                  1       /* Page State Change failure */
+#define GHCB_TERM_PVALIDATE            2       /* Pvalidate failure */
+
 #define GHCB_RESP_CODE(v)              ((v) & GHCB_MSR_INFO_MASK)
 
 /*

diff --git a/arch/x86/kernel/sev-shared.c b/arch/x86/kernel/sev-shared.c
index ce98768..2abf8a7 100644 (file)
--- a/arch/x86/kernel/sev-shared.c
+++ b/arch/x86/kernel/sev-shared.c
@@ -24,15 +24,12 @@ static bool __init sev_es_check_cpu_features(void)
        return true;
 }
 
-static void __noreturn sev_es_terminate(unsigned int reason)
+static void __noreturn sev_es_terminate(unsigned int set, unsigned int reason)
 {
        u64 val = GHCB_MSR_TERM_REQ;
 
-       /*
-        * Tell the hypervisor what went wrong - only reason-set 0 is
-        * currently supported.
-        */
-       val |= GHCB_SEV_TERM_REASON(0, reason);
+       /* Tell the hypervisor what went wrong. */
+       val |= GHCB_SEV_TERM_REASON(set, reason);
 
        /* Request Guest Termination from Hypvervisor */
        sev_es_wr_ghcb_msr(val);
@@ -221,7 +218,7 @@ void __init do_vc_no_ghcb(struct pt_regs *regs, unsigned long exit_code)
 
 fail:
        /* Terminate the guest */
-       sev_es_terminate(GHCB_SEV_ES_GEN_REQ);
+       sev_es_terminate(SEV_TERM_SET_GEN, GHCB_SEV_ES_GEN_REQ);
 }
 
 static enum es_result vc_insn_string_read(struct es_em_ctxt *ctxt,

diff --git a/arch/x86/kernel/sev.c b/arch/x86/kernel/sev.c
index e6d316a..19ad097 100644 (file)
--- a/arch/x86/kernel/sev.c
+++ b/arch/x86/kernel/sev.c
@@ -1337,7 +1337,7 @@ DEFINE_IDTENTRY_VC_KERNEL(exc_vmm_communication)
                show_regs(regs);
 
                /* Ask hypervisor to sev_es_terminate */
-               sev_es_terminate(GHCB_SEV_ES_GEN_REQ);
+               sev_es_terminate(SEV_TERM_SET_GEN, GHCB_SEV_ES_GEN_REQ);
 
                /* If that fails and we get here - just panic */
                panic("Returned from Terminate-Request to Hypervisor\n");
@@ -1385,7 +1385,7 @@ bool __init handle_vc_boot_ghcb(struct pt_regs *regs)
 
        /* Do initial setup or terminate the guest */
        if (unlikely(boot_ghcb == NULL && !sev_es_setup_ghcb()))
-               sev_es_terminate(GHCB_SEV_ES_GEN_REQ);
+               sev_es_terminate(SEV_TERM_SET_GEN, GHCB_SEV_ES_GEN_REQ);
 
        vc_ghcb_invalidate(boot_ghcb);