From: Tom Lendacky <thomas.lenda...@amd.com>

Implement a handler for #VC exceptions caused by VMMCALL instructions.
This patch is only a starting point, VMMCALL emulation under SEV-ES
needs further hypervisor-specific changes to provide additional state.

Signed-off-by: Tom Lendacky <thomas.lenda...@amd.com>
[ jroe...@suse.de: Adapt to #VC handling infrastructure ]
Co-developed-by: Joerg Roedel <jroe...@suse.de>
Signed-off-by: Joerg Roedel <jroe...@suse.de>
---
 arch/x86/kernel/sev-es.c | 23 +++++++++++++++++++++++
 1 file changed, 23 insertions(+)

diff --git a/arch/x86/kernel/sev-es.c b/arch/x86/kernel/sev-es.c
index 0d0b6e15f7d9..db8e33280f7a 100644
--- a/arch/x86/kernel/sev-es.c
+++ b/arch/x86/kernel/sev-es.c
@@ -889,6 +889,26 @@ static enum es_result vc_handle_mwait(struct ghcb *ghcb,
        return ES_OK;
 }
 
+static enum es_result vc_handle_vmmcall(struct ghcb *ghcb,
+                                       struct es_em_ctxt *ctxt)
+{
+       enum es_result ret;
+
+       ghcb_set_rax(ghcb, ctxt->regs->ax);
+       ghcb_set_cpl(ghcb, user_mode(ctxt->regs) ? 3 : 0);
+
+       ret = sev_es_ghcb_hv_call(ghcb, ctxt, SVM_EXIT_VMMCALL, 0, 0);
+       if (ret != ES_OK)
+               return ret;
+
+       if (!ghcb_rax_is_valid(ghcb))
+               return ES_VMM_ERROR;
+
+       ctxt->regs->ax = ghcb->save.rax;
+
+       return ES_OK;
+}
+
 static enum es_result vc_handle_exitcode(struct es_em_ctxt *ctxt,
                                         struct ghcb *ghcb,
                                         unsigned long exit_code)
@@ -922,6 +942,9 @@ static enum es_result vc_handle_exitcode(struct es_em_ctxt 
*ctxt,
        case SVM_EXIT_MSR:
                result = vc_handle_msr(ghcb, ctxt);
                break;
+       case SVM_EXIT_VMMCALL:
+               result = vc_handle_vmmcall(ghcb, ctxt);
+               break;
        case SVM_EXIT_WBINVD:
                result = vc_handle_wbinvd(ghcb, ctxt);
                break;
-- 
2.28.0

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