11:42 a.m.
Add checking in virt-host-validate for secure guest support
on x86 for AMD Secure Encrypted Virtualization.
Signed-off-by: Boris Fiuczynski <fiuczy(a)linux.ibm.com>
Reviewed-by: Paulo de Rezende Pinatti <ppinatti(a)linux.ibm.com>
Reviewed-by: Bjoern Walk <bwalk(a)linux.ibm.com>
---
docs/kbase/launch_security_sev.rst | 7 ++++--
tools/virt-host-validate-common.c | 36 ++++++++++++++++++++++++++++--
tools/virt-host-validate-common.h | 1 +
3 files changed, 40 insertions(+), 4 deletions(-)
diff --git a/docs/kbase/launch_security_sev.rst b/docs/kbase/launch_security_sev.rst
index fa602c7432..45166b3886 100644
--- a/docs/kbase/launch_security_sev.rst
+++ b/docs/kbase/launch_security_sev.rst
@@ -30,8 +30,11 @@ Enabling SEV on the host
========================
Before VMs can make use of the SEV feature you need to make sure your
-AMD CPU does support SEV. You can check whether SEV is among the CPU
-flags with:
+AMD CPU does support SEV. You can run ``libvirt-host-validate``
+(libvirt >= 6.4.0) to check if your host supports secure guests or you
+can follow the manual checks below.
+
+You can manually check whether SEV is among the CPU flags with:
::
diff --git a/tools/virt-host-validate-common.c b/tools/virt-host-validate-common.c
index dd73bd0dea..67aa420d35 100644
--- a/tools/virt-host-validate-common.c
+++ b/tools/virt-host-validate-common.c
@@ -41,7 +41,8 @@ VIR_ENUM_IMPL(virHostValidateCPUFlag,
"vmx",
"svm",
"sie",
- "158");
+ "158",
+ "sev");
static bool quiet;
@@ -447,15 +448,19 @@ int virHostValidateSecureGuests(const char *hvname,
virHostValidateLevel level)
{
virBitmapPtr flags;
- bool hasFac158 = false;
+ bool hasFac158 = false, hasAMDSev = false;
virArch arch = virArchFromHost();
g_autofree char *cmdline = NULL;
static const char *kIBMValues[] = {"y", "Y", "1"};
+ static const char *kAMDValues[] = {"on"};
+ g_autofree char *mod_value = NULL;
flags = virHostValidateGetCPUFlags();
if (flags && virBitmapIsBitSet(flags,
VIR_HOST_VALIDATE_CPU_FLAG_FACILITY_158))
hasFac158 = true;
+ else if (flags && virBitmapIsBitSet(flags, VIR_HOST_VALIDATE_CPU_FLAG_SEV))
+ hasAMDSev = true;
virBitmapFree(flags);
@@ -485,6 +490,33 @@ int virHostValidateSecureGuests(const char *hvname,
virHostMsgFail(level, "Hardware or firmware does not provide "
"support for IBM Secure Execution");
}
+ } else if (hasAMDSev) {
+ if (virFileReadValueString(&mod_value,
"/sys/module/kvm_amd/parameters/sev") < 0) {
+ virHostMsgFail(level, "AMD Secure Encrypted Virtualization not "
+ "supported by the currently used kernel");
+ return 0;
+ }
+ if (mod_value[0] != '1') {
+ virHostMsgFail(level,
+ "AMD Secure Encrypted Virtualization appears to be
"
+ "disabled in kernel. Add mem_encrypt=on "
+ "kvm_amd.sev=1 to kernel cmdline arguments");
+ return 0;
+ }
+ if (virFileReadValueString(&cmdline, "/proc/cmdline") < 0)
+ return -1;
+ if (virKernelCmdlineMatchParam(cmdline, "mem_encrypt", kAMDValues,
+ G_N_ELEMENTS(kAMDValues),
+ VIR_KERNEL_CMDLINE_FLAGS_SEARCH_LAST |
+ VIR_KERNEL_CMDLINE_FLAGS_CMP_EQ)) {
+ virHostMsgPass();
+ return 1;
+ } else {
+ virHostMsgFail(level,
+ "AMD Secure Encrypted Virtualization appears to be
"
+ "disabled in kernel. Add mem_encrypt=on "
+ "kvm_amd.sev=1 to kernel cmdline arguments");
+ }
} else {
virHostMsgFail(level,
"Unknown if this platform has Secure Guest support");
diff --git a/tools/virt-host-validate-common.h b/tools/virt-host-validate-common.h
index 44b5544a12..3df5ea0c7e 100644
--- a/tools/virt-host-validate-common.h
+++ b/tools/virt-host-validate-common.h
@@ -38,6 +38,7 @@ typedef enum {
VIR_HOST_VALIDATE_CPU_FLAG_SVM,
VIR_HOST_VALIDATE_CPU_FLAG_SIE,
VIR_HOST_VALIDATE_CPU_FLAG_FACILITY_158,
+ VIR_HOST_VALIDATE_CPU_FLAG_SEV,
VIR_HOST_VALIDATE_CPU_FLAG_LAST,
} virHostValidateCPUFlag;
--
2.25.1