On Thu, Mar 08, 2018 at 11:12:03AM -0600, Brijesh Singh wrote:
> QEMU >= 2.12 provides 'sev-guest' object which is used to launch encrypted
> VMs on AMD platform using SEV feature. The various inputs required to
> launch SEV guest is provided through the <launch-security> tag. A typical
> SEV guest launch command line looks like this:
>
> # $QEMU ...\
> -object sev-guest,id=sev0,cbitpos=47,reduced-phys-bits=5 ...\
> -machine memory-encryption=sev0 \
>
> Signed-off-by: Brijesh Singh <brijesh.singh@xxxxxxx>
> ---
> src/qemu/qemu_command.c | 33 ++++++++++++++++++
> src/qemu/qemu_process.c | 91 +++++++++++++++++++++++++++++++++++++++++++++++++
> 2 files changed, 124 insertions(+)
>
> diff --git a/src/qemu/qemu_command.c b/src/qemu/qemu_command.c
> index fa0aa5d5c3d4..39f136a389cb 100644
> --- a/src/qemu/qemu_command.c
> +++ b/src/qemu/qemu_command.c
> @@ -9663,6 +9663,36 @@ qemuBuildTPMCommandLine(virCommandPtr cmd,
> return 0;
> }
>
> +static void
> +qemuBuildSevCommandLine(virCommandPtr cmd,
> + virDomainSevDefPtr sev)
> +{
> + virBuffer obj = VIR_BUFFER_INITIALIZER;
> + char *path = NULL;
> +
> + VIR_DEBUG("policy=0x%x cbitpos=%d reduced_phys_bits=%d",
> + sev->policy, sev->cbitpos, sev->reduced_phys_bits);
> +
> + virCommandAddArgList(cmd, "-machine", "memory-encryption=sev0", NULL);
Hmm, so this will result in us passing '-machine' many times, and relying
on QEMU to acculate the args. It should work, but IME it could be a little
surprising to people debuggnig qemu to see repeated args for -machine.
Could we just call this method from the place that constructs the
current -machine arg so we append to that.
> +
> + virBufferAsprintf(&obj, "sev-guest,id=sev0,cbitpos=%d", sev->cbitpos);
> + virBufferAsprintf(&obj, ",reduced-phys-bits=%d", sev->reduced_phys_bits);
> + virBufferAsprintf(&obj, ",policy=0x%x", sev->policy);
> +
> + if (sev->dh_cert) {
> + ignore_value(virAsprintf(&path, "%s/dh_cert.base64", sev->configDir));
> + virBufferAsprintf(&obj, ",dh-cert-file=%s", path);
> + VIR_FREE(path);
> + }
> +
> + if (sev->session) {
> + ignore_value(virAsprintf(&path, "%s/session.base64", sev->configDir));
> + virBufferAsprintf(&obj, ",session-file=%s", path);
> + VIR_FREE(path);
> + }
> +
> + virCommandAddArgList(cmd, "-object", virBufferContentAndReset(&obj), NULL);
> +}
>
> static int
> qemuBuildVMCoreInfoCommandLine(virCommandPtr cmd,
> @@ -10108,6 +10138,9 @@ qemuBuildCommandLine(virQEMUDriverPtr driver,
> if (qemuBuildVMCoreInfoCommandLine(cmd, def, qemuCaps) < 0)
> goto error;
>
> + if (virQEMUCapsGet(qemuCaps, QEMU_CAPS_SEV) && def->sev)
> + qemuBuildSevCommandLine(cmd, def->sev);
> +
> if (snapshot)
> virCommandAddArgList(cmd, "-loadvm", snapshot->def->name, NULL);
>
> diff --git a/src/qemu/qemu_process.c b/src/qemu/qemu_process.c
> index 57c06c7c1550..349e12b6dc12 100644
> --- a/src/qemu/qemu_process.c
> +++ b/src/qemu/qemu_process.c
> @@ -3457,6 +3457,16 @@ qemuProcessBuildDestroyMemoryPathsImpl(virQEMUDriverPtr driver,
> }
>
>
> +static void
> +qemuProcessDestroySevPaths(virDomainSevDefPtr sev)
> +{
> + if (!sev)
> + return;
> +
> + virFileDeleteTree(sev->configDir);
Just delete the individual files we created, no recursive delete please.
> + VIR_FREE(sev->configDir);
> +}
> +
> int
> qemuProcessBuildDestroyMemoryPaths(virQEMUDriverPtr driver,
> virDomainObjPtr vm,
> @@ -5741,6 +5751,83 @@ qemuProcessPrepareDomain(virQEMUDriverPtr driver,
> return ret;
> }
>
> +static int
> +qemuBuildSevCreateFile(const char *configDir, const char *name,
> + const char *data)
> +{
> + char *configFile;
> +
> + if (!(configFile = virFileBuildPath(configDir, name, ".base64")))
> + return -1;
> +
> + if (virFileRewriteStr(configFile, S_IRUSR | S_IWUSR, data) < 0) {
> + virReportSystemError(errno, _("failed to write data to config '%s'"),
> + configFile);
> + goto error;
> + }
> +
> + VIR_FREE(configFile);
> + return 0;
> +
> + error:
> + VIR_FREE(configFile);
> + return -1;
> +}
> +
> +static int
> +qemuProcessPrepareSevGuestInput(virQEMUDriverPtr driver,
> + virDomainObjPtr vm)
> +{
> + qemuDomainObjPrivatePtr priv = vm->privateData;
> + virDomainDefPtr def = vm->def;
> + virQEMUCapsPtr qemuCaps = priv->qemuCaps;
> + virDomainSevDefPtr sev = def->sev;
> + char *configDir = NULL;
> + char *domPath = virDomainDefGetShortName(def);
> + virQEMUDriverConfigPtr cfg = virQEMUDriverGetConfig(driver);
> +
> + if (!sev)
> + return 0;
> +
> + VIR_DEBUG("Prepare SEV guest");
> +
> + if (!virQEMUCapsGet(qemuCaps, QEMU_CAPS_SEV)) {
> + virReportError(VIR_ERR_INTERNAL_ERROR,
> + _("Domain %s asked for 'sev' launch but "
> + "QEMU does not support SEV feature"), vm->def->name);
> + return -1;
> + }
> +
> + if (virAsprintf(&configDir, "%s/sev/%s", cfg->configDir, domPath) < 0)
> + goto error;
We already have a directory where we put transient things like the QEMU
monitor socket, pid file, etc. This is defineed by 'priv->libDir', so
just use that directory and don't create extra sub-dirs.
> + if (virFileMakePathWithMode(configDir, S_IRWXU) < 0) {
> + virReportSystemError(errno, _("cannot create config directory '%s'"),
> + configDir);
> + goto error;
> + }
> +
> + if (sev->dh_cert) {
> + if (qemuBuildSevCreateFile(configDir, "dh_cert", sev->dh_cert) < 0)
> + goto error1;
> + }
> +
> + if (sev->session) {
> + if (qemuBuildSevCreateFile(configDir, "session", sev->session) < 0)
> + goto error1;
> + }
> +
> + VIR_FREE(domPath);
> + sev->configDir = configDir;
> + return 0;
> +
> + error1:
> + virFileDeleteTree(configDir);
> + error:
> + VIR_FREE(configDir);
> + VIR_FREE(domPath);
> + return -1;
> +}
>
> static int
> qemuProcessPrepareHostStorage(virQEMUDriverPtr driver,
> @@ -5866,6 +5953,9 @@ qemuProcessPrepareHost(virQEMUDriverPtr driver,
> if (qemuProcessPrepareHostStorage(driver, vm, flags) < 0)
> goto cleanup;
>
> + if (qemuProcessPrepareSevGuestInput(driver, vm) < 0)
> + goto cleanup;
> +
> ret = 0;
> cleanup:
> virObjectUnref(cfg);
> @@ -6535,6 +6625,7 @@ void qemuProcessStop(virQEMUDriverPtr driver,
> }
>
> qemuProcessBuildDestroyMemoryPaths(driver, vm, NULL, false);
> + qemuProcessDestroySevPaths(vm->def->sev);
>
> vm->def->id = -1;
>
> --
> 2.14.3
>
Regards,
Daniel
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