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Subject[PATCH Part1 RFC v3 02/22] x86/sev: Define the Linux specific guest termination reasons
Date
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 | 5 +++++
arch/x86/kernel/sev-shared.c | 6 +++---
arch/x86/kernel/sev.c | 4 ++--
4 files changed, 13 insertions(+), 8 deletions(-)

diff --git a/arch/x86/boot/compressed/sev.c b/arch/x86/boot/compressed/sev.c
index 28bcf04c022e..87621f4e4703 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(0, 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(0, GHCB_SEV_ES_GEN_REQ);

vc_ghcb_invalidate(boot_ghcb);
result = vc_init_em_ctxt(&ctxt, regs, exit_code);
@@ -202,5 +202,5 @@ 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(0, GHCB_SEV_ES_GEN_REQ);
}
diff --git a/arch/x86/include/asm/sev-common.h b/arch/x86/include/asm/sev-common.h
index 11b7d9cea775..f1e2aacb0d61 100644
--- a/arch/x86/include/asm/sev-common.h
+++ b/arch/x86/include/asm/sev-common.h
@@ -59,4 +59,9 @@

#define GHCB_RESP_CODE(v) ((v) & GHCB_MSR_INFO_MASK)

+/* Linux specific reason codes (used with reason set 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 */
+
#endif
diff --git a/arch/x86/kernel/sev-shared.c b/arch/x86/kernel/sev-shared.c
index 14198075ff8b..de0e7e6c52b8 100644
--- a/arch/x86/kernel/sev-shared.c
+++ b/arch/x86/kernel/sev-shared.c
@@ -24,7 +24,7 @@ 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;

@@ -32,7 +32,7 @@ static void __noreturn sev_es_terminate(unsigned int reason)
* Tell the hypervisor what went wrong - only reason-set 0 is
* currently supported.
*/
- val |= GHCB_SEV_TERM_REASON(0, reason);
+ val |= GHCB_SEV_TERM_REASON(set, reason);

/* Request Guest Termination from Hypvervisor */
sev_es_wr_ghcb_msr(val);
@@ -207,7 +207,7 @@ 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(0, 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 460717e3f72d..77a754365ba9 100644
--- a/arch/x86/kernel/sev.c
+++ b/arch/x86/kernel/sev.c
@@ -1383,7 +1383,7 @@ DEFINE_IDTENTRY_VC_SAFE_STACK(exc_vmm_communication)
show_regs(regs);

/* Ask hypervisor to sev_es_terminate */
- sev_es_terminate(GHCB_SEV_ES_GEN_REQ);
+ sev_es_terminate(0, GHCB_SEV_ES_GEN_REQ);

/* If that fails and we get here - just panic */
panic("Returned from Terminate-Request to Hypervisor\n");
@@ -1416,7 +1416,7 @@ 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(0, GHCB_SEV_ES_GEN_REQ);

vc_ghcb_invalidate(boot_ghcb);

--
2.17.1
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