x86/sev-es: Handle VMMCALL Events

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

 [ bp: Drop "this patch". ]

Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
[ jroedel@suse.de: Adapt to #VC handling infrastructure ]
Co-developed-by: Joerg Roedel <jroedel@suse.de>
Signed-off-by: Joerg Roedel <jroedel@suse.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20200907131613.12703-60-joro@8bytes.org

diff --git a/arch/x86/kernel/sev-es.c b/arch/x86/kernel/sev-es.c
index 2aea903..86cb4c5 100644 (file)
--- 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;