Re: [PATCH v3 2/7] crypto: ccp: Fix implicit SEV/SNP init and shutdown in ioctls

Dionna Amalie Glaze
2025-01-06T18:01:52Z

On Fri, Jan 3, 2025 at 12:00 PM Ashish Kalra <Ashish.Kalra@amd.com> wrote:
>
> From: Ashish Kalra <ashish.kalra@amd.com>
>

The subject includes "Fix" but has no "Fixes" tag in the commit message.

> Modify the behavior of implicit SEV initialization in some of the
> SEV ioctls to do both SEV initialization and shutdown and adds
> implicit SNP initialization and shutdown to some of the SNP ioctls
> so that the change of SEV/SNP platform initialization not being
> done during PSP driver probe time does not break userspace tools
> such as sevtool, etc.
>

It would be helpful to update the description with the state machine
you're trying to maintain implicitly.
I think that this changes the uapi contract as well, so I think you
need to update the documentation.

You have SEV shutdown on error for platform maintenance ioctls here,
which already have implicit init.
pdh_export gets an init if not in the init state, which wasn't already
implicit because there's a wrinkle WRT the writability permission.

snp_platform_status, snp_config, vlek_load, snp_commit now should be
callable any time, not just when KVM has initialized SNP? If there's a
caveat to the platform status, the docs need to reflect it.
I don't know how SNP_COMMIT makes sense as having an implicit
init/shutdown unless you're using it as SET_CONFIG, but I suppose it
doesn't hurt?

> Signed-off-by: Ashish Kalra <ashish.kalra@amd.com>
> ---
> drivers/crypto/ccp/sev-dev.c | 149 +++++++++++++++++++++++++++++------
> 1 file changed, 125 insertions(+), 24 deletions(-)
>
> diff --git a/drivers/crypto/ccp/sev-dev.c b/drivers/crypto/ccp/sev-dev.c
> index 1c1c33d3ed9a..0ec2e8191583 100644
> --- a/drivers/crypto/ccp/sev-dev.c
> +++ b/drivers/crypto/ccp/sev-dev.c
> @@ -1454,7 +1454,8 @@ static int sev_ioctl_do_platform_status(struct sev_issue_cmd *argp)
> static int sev_ioctl_do_pek_pdh_gen(int cmd, struct sev_issue_cmd *argp, bool writable)
> {
> struct sev_device *sev = psp_master->sev_data;
> - int rc;
> + bool shutdown_required = false;
> + int rc, ret, error;
>
> if (!writable)
> return -EPERM;
> @@ -1463,19 +1464,30 @@ static int sev_ioctl_do_pek_pdh_gen(int cmd, struct sev_issue_cmd *argp, bool wr
> rc = __sev_platform_init_locked(&argp->error);
> if (rc)
> return rc;
> + shutdown_required = true;
> + }
> +
> + rc = __sev_do_cmd_locked(cmd, NULL, &argp->error);
> +
> + if (shutdown_required) {
> + ret = __sev_platform_shutdown_locked(&error);
> + if (ret)
> + dev_err(sev->dev, "SEV: failed to SHUTDOWN error %#x, rc %d\n",
> + error, ret);
> }
>
> - return __sev_do_cmd_locked(cmd, NULL, &argp->error);
> + return rc;
> }
>
> static int sev_ioctl_do_pek_csr(struct sev_issue_cmd *argp, bool writable)
> {
> struct sev_device *sev = psp_master->sev_data;
> struct sev_user_data_pek_csr input;
> + bool shutdown_required = false;
> struct sev_data_pek_csr data;
> void __user *input_address;
> + int ret, rc, error;
> void *blob = NULL;
> - int ret;
>
> if (!writable)
> return -EPERM;
> @@ -1506,6 +1518,7 @@ static int sev_ioctl_do_pek_csr(struct sev_issue_cmd *argp, bool writable)
> ret = __sev_platform_init_locked(&argp->error);
> if (ret)
> goto e_free_blob;
> + shutdown_required = true;
> }
>
> ret = __sev_do_cmd_locked(SEV_CMD_PEK_CSR, &data, &argp->error);
> @@ -1524,6 +1537,13 @@ static int sev_ioctl_do_pek_csr(struct sev_issue_cmd *argp, bool writable)
> }
>
> e_free_blob:
> + if (shutdown_required) {
> + rc = __sev_platform_shutdown_locked(&error);
> + if (rc)
> + dev_err(sev->dev, "SEV: failed to SHUTDOWN error %#x, rc %d\n",
> + error, rc);
> + }
> +
> kfree(blob);
> return ret;
> }
> @@ -1739,8 +1759,9 @@ static int sev_ioctl_do_pek_import(struct sev_issue_cmd *argp, bool writable)
> struct sev_device *sev = psp_master->sev_data;
> struct sev_user_data_pek_cert_import input;
> struct sev_data_pek_cert_import data;
> + bool shutdown_required = false;
> void *pek_blob, *oca_blob;
> - int ret;
> + int ret, rc, error;
>
> if (!writable)
> return -EPERM;
> @@ -1772,11 +1793,19 @@ static int sev_ioctl_do_pek_import(struct sev_issue_cmd *argp, bool writable)
> ret = __sev_platform_init_locked(&argp->error);
> if (ret)
> goto e_free_oca;
> + shutdown_required = true;
> }
>
> ret = __sev_do_cmd_locked(SEV_CMD_PEK_CERT_IMPORT, &data, &argp->error);
>
> e_free_oca:
> + if (shutdown_required) {
> + rc = __sev_platform_shutdown_locked(&error);
> + if (rc)
> + dev_err(sev->dev, "SEV: failed to SHUTDOWN error %#x, rc %d\n",
> + error, rc);
> + }
> +
> kfree(oca_blob);
> e_free_pek:
> kfree(pek_blob);
> @@ -1893,17 +1922,8 @@ static int sev_ioctl_do_pdh_export(struct sev_issue_cmd *argp, bool writable)
> struct sev_data_pdh_cert_export data;
> void __user *input_cert_chain_address;
> void __user *input_pdh_cert_address;
> - int ret;
> -
> - /* If platform is not in INIT state then transition it to INIT. */
> - if (sev->state != SEV_STATE_INIT) {
> - if (!writable)
> - return -EPERM;
> -
> - ret = __sev_platform_init_locked(&argp->error);
> - if (ret)
> - return ret;
> - }
> + bool shutdown_required = false;
> + int ret, rc, error;
>
> if (copy_from_user(&input, (void __user *)argp->data, sizeof(input)))
> return -EFAULT;
> @@ -1944,6 +1964,16 @@ static int sev_ioctl_do_pdh_export(struct sev_issue_cmd *argp, bool writable)
> data.cert_chain_len = input.cert_chain_len;
>
> cmd:
> + /* If platform is not in INIT state then transition it to INIT. */
> + if (sev->state != SEV_STATE_INIT) {
> + if (!writable)
> + return -EPERM;
> + ret = __sev_platform_init_locked(&argp->error);
> + if (ret)
> + goto e_free_cert;
> + shutdown_required = true;
> + }
> +
> ret = __sev_do_cmd_locked(SEV_CMD_PDH_CERT_EXPORT, &data, &argp->error);
>
> /* If we query the length, FW responded with expected data. */
> @@ -1970,6 +2000,13 @@ static int sev_ioctl_do_pdh_export(struct sev_issue_cmd *argp, bool writable)
> }
>
> e_free_cert:
> + if (shutdown_required) {
> + rc = __sev_platform_shutdown_locked(&error);
> + if (rc)
> + dev_err(sev->dev, "SEV: failed to SHUTDOWN error %#x, rc %d\n",
> + error, rc);
> + }
> +
> kfree(cert_blob);
> e_free_pdh:
> kfree(pdh_blob);
> @@ -1979,12 +2016,13 @@ static int sev_ioctl_do_pdh_export(struct sev_issue_cmd *argp, bool writable)
> static int sev_ioctl_do_snp_platform_status(struct sev_issue_cmd *argp)
> {
> struct sev_device *sev = psp_master->sev_data;
> + bool shutdown_required = false;
> struct sev_data_snp_addr buf;
> struct page *status_page;
> + int ret, rc, error;
> void *data;
> - int ret;
>
> - if (!sev->snp_initialized || !argp->data)
> + if (!argp->data)
> return -EINVAL;
>
> status_page = alloc_page(GFP_KERNEL_ACCOUNT);
> @@ -1993,6 +2031,13 @@ static int sev_ioctl_do_snp_platform_status(struct sev_issue_cmd *argp)
>
> data = page_address(status_page);
>
> + if (!sev->snp_initialized) {
> + ret = __sev_snp_init_locked(&argp->error);
> + if (ret)
> + goto cleanup;
> + shutdown_required = true;
> + }
> +
> /*
> * Firmware expects status page to be in firmware-owned state, otherwise
> * it will report firmware error code INVALID_PAGE_STATE (0x1A).
> @@ -2021,6 +2066,13 @@ static int sev_ioctl_do_snp_platform_status(struct sev_issue_cmd *argp)
> ret = -EFAULT;
>
> cleanup:
> + if (shutdown_required) {
> + rc = __sev_snp_shutdown_locked(&error, false);
> + if (rc)
> + dev_err(sev->dev, "SEV-SNP: failed to SHUTDOWN error %#x, rc %d\n",
> + error, rc);
> + }
> +
> __free_pages(status_page, 0);
> return ret;
> }
> @@ -2029,21 +2081,38 @@ static int sev_ioctl_do_snp_commit(struct sev_issue_cmd *argp)
> {
> struct sev_device *sev = psp_master->sev_data;
> struct sev_data_snp_commit buf;
> + bool shutdown_required = false;
> + int ret, rc, error;
>
> - if (!sev->snp_initialized)
> - return -EINVAL;
> + if (!sev->snp_initialized) {
> + ret = __sev_snp_init_locked(&argp->error);
> + if (ret)
> + return ret;
> + shutdown_required = true;
> + }
>
> buf.len = sizeof(buf);
>
> - return __sev_do_cmd_locked(SEV_CMD_SNP_COMMIT, &buf, &argp->error);
> + ret = __sev_do_cmd_locked(SEV_CMD_SNP_COMMIT, &buf, &argp->error);
> +
> + if (shutdown_required) {
> + rc = __sev_snp_shutdown_locked(&error, false);
> + if (rc)
> + dev_err(sev->dev, "SEV-SNP: failed to SHUTDOWN error %#x, rc %d\n",
> + error, rc);
> + }
> +
> + return ret;
> }
>
> static int sev_ioctl_do_snp_set_config(struct sev_issue_cmd *argp, bool writable)
> {
> struct sev_device *sev = psp_master->sev_data;
> struct sev_user_data_snp_config config;
> + bool shutdown_required = false;
> + int ret, rc, error;
>
> - if (!sev->snp_initialized || !argp->data)
> + if (!argp->data)
> return -EINVAL;
>
> if (!writable)
> @@ -2052,17 +2121,34 @@ static int sev_ioctl_do_snp_set_config(struct sev_issue_cmd *argp, bool writable
> if (copy_from_user(&config, (void __user *)argp->data, sizeof(config)))
> return -EFAULT;
>
> - return __sev_do_cmd_locked(SEV_CMD_SNP_CONFIG, &config, &argp->error);
> + if (!sev->snp_initialized) {
> + ret = __sev_snp_init_locked(&argp->error);
> + if (ret)
> + return ret;
> + shutdown_required = true;
> + }
> +
> + ret = __sev_do_cmd_locked(SEV_CMD_SNP_CONFIG, &config, &argp->error);
> +
> + if (shutdown_required) {
> + rc = __sev_snp_shutdown_locked(&error, false);
> + if (rc)
> + dev_err(sev->dev, "SEV-SNP: failed to SHUTDOWN error %#x, rc %d\n",
> + error, rc);
> + }
> +
> + return ret;
> }
>
> static int sev_ioctl_do_snp_vlek_load(struct sev_issue_cmd *argp, bool writable)
> {
> struct sev_device *sev = psp_master->sev_data;
> struct sev_user_data_snp_vlek_load input;
> + bool shutdown_required = false;
> + int ret, rc, error;
> void *blob;
> - int ret;
>
> - if (!sev->snp_initialized || !argp->data)
> + if (!argp->data)
> return -EINVAL;
>
> if (!writable)
> @@ -2081,8 +2167,23 @@ static int sev_ioctl_do_snp_vlek_load(struct sev_issue_cmd *argp, bool writable)
>
> input.vlek_wrapped_address = __psp_pa(blob);
>
> + if (!sev->snp_initialized) {
> + ret = __sev_snp_init_locked(&argp->error);
> + if (ret)
> + goto cleanup;
> + shutdown_required = true;
> + }
> +
> ret = __sev_do_cmd_locked(SEV_CMD_SNP_VLEK_LOAD, &input, &argp->error);
>
> + if (shutdown_required) {
> + rc = __sev_snp_shutdown_locked(&error, false);
> + if (rc)
> + dev_err(sev->dev, "SEV-SNP: failed to SHUTDOWN error %#x, rc %d\n",
> + error, rc);
> + }
> +
> +cleanup:
> kfree(blob);
>
> return ret;
> --
> 2.34.1
>

--
-Dionna Glaze, PhD, CISSP, CCSP (she/her)