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[v8,04/40] x86/sev: Define the Linux specific guest termination reasons

Message ID 20211210154332.11526-5-brijesh.singh@amd.com (mailing list archive)
State New, archived
Headers show
Series Add AMD Secure Nested Paging (SEV-SNP) Guest Support | expand

Commit Message

Brijesh Singh Dec. 10, 2021, 3:42 p.m. UTC 
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 set 1 to 255 is reserved for the vendor-specific codes.
Reseve the reason set 1 for the Linux guest. Define an error codes for
reason set 1.

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

Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
---
 arch/x86/boot/compressed/sev.c    |  6 +++---
 arch/x86/include/asm/sev-common.h |  8 ++++++++
 arch/x86/kernel/sev-shared.c      | 11 ++++-------
 arch/x86/kernel/sev.c             |  4 ++--
 4 files changed, 17 insertions(+), 12 deletions(-)

Comments

Venu Busireddy Dec. 14, 2021, 12:13 a.m. UTC | #1 
On 2021-12-10 09:42:56 -0600, Brijesh Singh wrote:
> 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 set 1 to 255 is reserved for the vendor-specific codes.

s/set 1 to 255 is/sets 1 to 255 are/

> Reseve the reason set 1 for the Linux guest. Define an error codes for

s/Define an/Define the/

> reason set 1.
> 
> While at it, change the sev_es_terminate() to accept the reason set
> parameter.
> 
> Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>

With that...

Reviewed-by: Venu Busireddy <venu.busireddy@oracle.com>

> ---
>  arch/x86/boot/compressed/sev.c    |  6 +++---
>  arch/x86/include/asm/sev-common.h |  8 ++++++++
>  arch/x86/kernel/sev-shared.c      | 11 ++++-------
>  arch/x86/kernel/sev.c             |  4 ++--
>  4 files changed, 17 insertions(+), 12 deletions(-)
Borislav Petkov Dec. 14, 2021, 10:22 p.m. UTC | #2 
On Fri, Dec 10, 2021 at 09:42:56AM -0600, Brijesh Singh wrote:
> 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 set 1 to 255 is reserved for the vendor-specific codes.
> Reseve the reason set 1 for the Linux guest. Define an error codes for

Yah, your spellchecker is still broken:

Reseve the reason set 1 for the Linux guest. Define an error codes for
Unknown word [Reseve] in commit message, suggestions:
        ['Reeves', 'Reeve', 'Reserve', 'Res eve', 'Res-eve', 'Severe', 'Reverse', 'Sevres', 'Revers']

> reason set 1.

"... and use them in the Linux guest so that one can have meaningful
termination reasons and thus better guest failure diagnosis."

The *why* is very important.
diff mbox series

Patch

diff --git a/arch/x86/boot/compressed/sev.c b/arch/x86/boot/compressed/sev.c
index 8eebdf589a90..0b6cc6402ac1 100644
--- a/arch/x86/boot/compressed/sev.c
+++ b/arch/x86/boot/compressed/sev.c
@@ -122,7 +122,7 @@  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;
@@ -175,7 +175,7 @@  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);
@@ -202,7 +202,7 @@  void do_boot_stage2_vc(struct pt_regs *regs, unsigned long exit_code)
 	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);
 }
 
 static inline u64 rd_sev_status_msr(void)
diff --git a/arch/x86/include/asm/sev-common.h b/arch/x86/include/asm/sev-common.h
index 1b2fd32b42fe..94f0ea574049 100644
--- 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 ce987688bbc0..2abf8a7d75e5 100644
--- 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 e6d316a01fdd..19ad09712902 100644
--- 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);