[PATCH V5 8/8] x86/hyperv: Add hyperv-specific handling for VMMCALL under SEV-ES

From: Tianyu Lan
Date: Thu Aug 10 2023 - 12:13:12 EST


From: Tianyu Lan <tiala@xxxxxxxxxxxxx>

Add Hyperv-specific handling for faults caused by VMMCALL
instructions.

Reviewed-by: Michael Kelley <mikelley@xxxxxxxxxxxxx>
Signed-off-by: Tianyu Lan <tiala@xxxxxxxxxxxxx>
---
arch/x86/kernel/cpu/mshyperv.c | 21 +++++++++++++++++++++
1 file changed, 21 insertions(+)

diff --git a/arch/x86/kernel/cpu/mshyperv.c b/arch/x86/kernel/cpu/mshyperv.c
index c2ccb49b49c2..b7d73f3107c6 100644
--- a/arch/x86/kernel/cpu/mshyperv.c
+++ b/arch/x86/kernel/cpu/mshyperv.c
@@ -32,6 +32,7 @@
#include <asm/nmi.h>
#include <clocksource/hyperv_timer.h>
#include <asm/numa.h>
+#include <asm/svm.h>

/* Is Linux running as the root partition? */
bool hv_root_partition;
@@ -574,6 +575,22 @@ static bool __init ms_hyperv_msi_ext_dest_id(void)
return eax & HYPERV_VS_PROPERTIES_EAX_EXTENDED_IOAPIC_RTE;
}

+#ifdef CONFIG_AMD_MEM_ENCRYPT
+static void hv_sev_es_hcall_prepare(struct ghcb *ghcb, struct pt_regs *regs)
+{
+ /* RAX and CPL are already in the GHCB */
+ ghcb_set_rcx(ghcb, regs->cx);
+ ghcb_set_rdx(ghcb, regs->dx);
+ ghcb_set_r8(ghcb, regs->r8);
+}
+
+static bool hv_sev_es_hcall_finish(struct ghcb *ghcb, struct pt_regs *regs)
+{
+ /* No checking of the return state needed */
+ return true;
+}
+#endif
+
const __initconst struct hypervisor_x86 x86_hyper_ms_hyperv = {
.name = "Microsoft Hyper-V",
.detect = ms_hyperv_platform,
@@ -581,4 +598,8 @@ const __initconst struct hypervisor_x86 x86_hyper_ms_hyperv = {
.init.x2apic_available = ms_hyperv_x2apic_available,
.init.msi_ext_dest_id = ms_hyperv_msi_ext_dest_id,
.init.init_platform = ms_hyperv_init_platform,
+#ifdef CONFIG_AMD_MEM_ENCRYPT
+ .runtime.sev_es_hcall_prepare = hv_sev_es_hcall_prepare,
+ .runtime.sev_es_hcall_finish = hv_sev_es_hcall_finish,
+#endif
};
--
2.25.1