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Date: Mon, 1 Nov 2021 09:30:01 -0700
From: Marc Orr <marcorr@...gle.com>
To: Peter Gonda <pgonda@...gle.com>
Cc: Thomas.Lendacky@....com, David Rientjes <rientjes@...gle.com>,
Brijesh Singh <brijesh.singh@....com>,
Joerg Roedel <jroedel@...e.de>,
Herbert Xu <herbert@...dor.apana.org.au>,
John Allen <john.allen@....com>,
"David S. Miller" <davem@...emloft.net>,
Paolo Bonzini <pbonzini@...hat.com>,
linux-crypto@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 4/4] crypto: ccp - Add SEV_INIT_EX support
On Thu, Oct 28, 2021 at 10:58 AM Peter Gonda <pgonda@...gle.com> wrote:
>
> From: David Rientjes <rientjes@...gle.com>
>
> Add new module parameter to allow users to use SEV_INIT_EX instead of
> SEV_INIT. This helps users who lock their SPI bus to use the PSP for SEV
> functionality. The 'init_ex_path' parameter defaults to NULL which means
> the kernel will use SEV_INIT, if a path is specified SEV_INIT_EX will be
> used with the data found at the path. On certain PSP commands this
> file is written to as the PSP updates the NV memory region. Depending on
> file system initialization this file open may fail during module init
> but the CCP driver for SEV already has sufficient retries for platform
> initialization. During normal operation of PSP system and SEV commands
> if the PSP has not been initialized it is at run time.
>
> Signed-off-by: David Rientjes <rientjes@...gle.com>
> Co-developed-by: Peter Gonda <pgonda@...gle.com>
> Signed-off-by: Peter Gonda <pgonda@...gle.com>
> Cc: Tom Lendacky <thomas.lendacky@....com>
> Cc: Brijesh Singh <brijesh.singh@....com>
> Cc: Marc Orr <marcorr@...gle.com>
> Cc: Joerg Roedel <jroedel@...e.de>
> Cc: Herbert Xu <herbert@...dor.apana.org.au>
> Cc: David Rientjes <rientjes@...gle.com>
> Cc: John Allen <john.allen@....com>
> Cc: "David S. Miller" <davem@...emloft.net>
> Cc: Paolo Bonzini <pbonzini@...hat.com> (
> Cc: linux-crypto@...r.kernel.org
> Cc: linux-kernel@...r.kernel.org
> ---
> drivers/crypto/ccp/sev-dev.c | 186 ++++++++++++++++++++++++++++++++---
> include/linux/psp-sev.h | 21 ++++
> 2 files changed, 192 insertions(+), 15 deletions(-)
>
> diff --git a/drivers/crypto/ccp/sev-dev.c b/drivers/crypto/ccp/sev-dev.c
> index b568ae734857..c8718b4cbc93 100644
> --- a/drivers/crypto/ccp/sev-dev.c
> +++ b/drivers/crypto/ccp/sev-dev.c
> @@ -22,6 +22,7 @@
> #include <linux/firmware.h>
> #include <linux/gfp.h>
> #include <linux/cpufeature.h>
> +#include <linux/fs.h>
>
> #include <asm/smp.h>
>
> @@ -43,6 +44,10 @@ static int psp_probe_timeout = 5;
> module_param(psp_probe_timeout, int, 0644);
> MODULE_PARM_DESC(psp_probe_timeout, " default timeout value, in seconds, during PSP device probe");
>
> +static char *init_ex_path;
> +module_param(init_ex_path, charp, 0660);
> +MODULE_PARM_DESC(init_ex_path, " Path for INIT_EX data; if set try INIT_EX");
> +
> MODULE_FIRMWARE("amd/amd_sev_fam17h_model0xh.sbin"); /* 1st gen EPYC */
> MODULE_FIRMWARE("amd/amd_sev_fam17h_model3xh.sbin"); /* 2nd gen EPYC */
> MODULE_FIRMWARE("amd/amd_sev_fam19h_model0xh.sbin"); /* 3rd gen EPYC */
> @@ -58,6 +63,14 @@ static int psp_timeout;
> #define SEV_ES_TMR_SIZE (1024 * 1024)
> static void *sev_es_tmr;
>
> +/* INIT_EX NV Storage:
> + * The NV Storage is a 32Kb area and must be 4Kb page aligned. Use the page
> + * allocator to allocate the memory, which will return aligned memory for the
> + * specified allocation order.
> + */
> +#define NV_LENGTH (32 << 10)
> +static void *sev_init_ex_nv_address;
> +
> static inline bool sev_version_greater_or_equal(u8 maj, u8 min)
> {
> struct sev_device *sev = psp_master->sev_data;
> @@ -135,6 +148,7 @@ static int sev_cmd_buffer_len(int cmd)
> case SEV_CMD_GET_ID: return sizeof(struct sev_data_get_id);
> case SEV_CMD_ATTESTATION_REPORT: return sizeof(struct sev_data_attestation_report);
> case SEV_CMD_SEND_CANCEL: return sizeof(struct sev_data_send_cancel);
> + case SEV_CMD_INIT_EX: return sizeof(struct sev_data_init_ex);
> default: return 0;
> }
>
> @@ -156,6 +170,89 @@ static void *sev_fw_alloc(unsigned long len)
> return page_address(page);
> }
>
> +static int sev_read_nv_memory(void)
> +{
> + struct file *fp;
> + ssize_t nread;
> +
> + if (!sev_init_ex_nv_address)
> + return -EOPNOTSUPP;
> +
> + fp = filp_open(init_ex_path, O_RDONLY, 0);
> + if (IS_ERR(fp)) {
> + dev_err(psp_master->dev, "sev could not open file for read\n");
> + return PTR_ERR(fp);
> + }
> +
> + nread = kernel_read(fp, sev_init_ex_nv_address, NV_LENGTH, 0);
> + dev_dbg(psp_master->dev, "sev NV read %d bytes\n", nread);
> + filp_close(fp, NULL);
> + return 0;
> +}
> +
> +static int sev_write_nv_memory(void)
> +{
> + struct sev_device *sev = psp_master->sev_data;
> + struct file *fp;
> + loff_t offset = 0;
> + int ret;
> +
> + if (!sev_init_ex_nv_address)
> + return -EOPNOTSUPP;
> +
> + fp = filp_open(init_ex_path, O_CREAT | O_WRONLY, 0600);
> + if (IS_ERR(fp)) {
> + dev_err(sev->dev, "sev NV data could not be created\n");
> + return PTR_ERR(fp);
> + }
> + ret = kernel_write(fp, sev_init_ex_nv_address, NV_LENGTH, &offset);
> + vfs_fsync(fp, 0);
> + filp_close(fp, NULL);
> +
> + if (ret != NV_LENGTH) {
> + dev_err(sev->dev,
> + "failed to write %d bytes to non volatile memory area, ret=%lu\n",
> + NV_LENGTH, ret);
> + if (ret >= 0)
> + return -EIO;
> + return ret;
> + }
> +
> + dev_dbg(sev->dev, "wrote to non volatile memory area\n");
> + return 0;
> +}
> +
> +static void sev_write_nv_memory_if_required(int cmd_id)
> +{
> + struct sev_device *sev = psp_master->sev_data;
> + int ret;
> +
> + if (!sev_init_ex_nv_address)
> + return;
> +
> + /*
> + * Only a few platform commands modify the SPI/NV area,
> + * but none of the non-platform commands do. Only INIT,
> + * PLATFORM_RESET, PEK_GEN, PEK_CERT_IMPORT, and
> + * PDH_GEN do.
> + */
> + switch (cmd_id) {
> + case SEV_CMD_FACTORY_RESET:
> + case SEV_CMD_INIT_EX:
> + case SEV_CMD_PDH_GEN:
> + case SEV_CMD_PEK_CERT_IMPORT:
> + case SEV_CMD_PEK_GEN:
> + case SEV_CMD_SHUTDOWN:
> + break;
> + default:
> + return;
> + };
> +
> + ret = sev_write_nv_memory();
> + if (ret)
> + dev_err(sev->dev, "sev NV write failed %d\n", ret);
> +}
> +
> static int __sev_do_cmd_locked(int cmd, void *data, int *psp_ret)
> {
> struct psp_device *psp = psp_master;
> @@ -225,6 +322,8 @@ static int __sev_do_cmd_locked(int cmd, void *data, int *psp_ret)
> dev_dbg(sev->dev, "sev command %#x failed (%#010x)\n",
> cmd, reg & PSP_CMDRESP_ERR_MASK);
> ret = -EIO;
> + } else {
> + sev_write_nv_memory_if_required(cmd);
> }
>
> print_hex_dump_debug("(out): ", DUMP_PREFIX_OFFSET, 16, 2, data,
> @@ -251,22 +350,42 @@ static int sev_do_cmd(int cmd, void *data, int *psp_ret)
> return rc;
> }
>
> -static int __sev_platform_init_locked(int *error)
> +static int __sev_init_locked(int *error)
> {
> - struct psp_device *psp = psp_master;
> struct sev_data_init data;
> - struct sev_device *sev;
> - int rc = 0;
>
> - if (!psp || !psp->sev_data)
> - return -ENODEV;
> + memset(&data, 0, sizeof(data));
> + if (sev_es_tmr) {
> + u64 tmr_pa;
>
> - sev = psp->sev_data;
> + /*
> + * Do not include the encryption mask on the physical
> + * address of the TMR (firmware should clear it anyway).
> + */
> + tmr_pa = __pa(sev_es_tmr);
>
> - if (sev->state == SEV_STATE_INIT)
> - return 0;
> + data.flags |= SEV_INIT_FLAGS_SEV_ES;
> + data.tmr_address = tmr_pa;
> + data.tmr_len = SEV_ES_TMR_SIZE;
> + }
> +
> + return __sev_do_cmd_locked(SEV_CMD_INIT, &data, error);
> +}
> +
> +static int __sev_init_ex_locked(int *error)
> +{
> + struct sev_data_init_ex data;
> + int ret;
>
> memset(&data, 0, sizeof(data));
> + data.length = sizeof(data);
> + data.nv_address = __psp_pa(sev_init_ex_nv_address);
> + data.nv_len = NV_LENGTH;
> +
> + ret = sev_read_nv_memory();
> + if (ret)
> + return ret;
> +
> if (sev_es_tmr) {
> u64 tmr_pa;
>
> @@ -276,12 +395,30 @@ static int __sev_platform_init_locked(int *error)
> */
> tmr_pa = __pa(sev_es_tmr);
>
> - data.flags |= SEV_INIT_FLAGS_SEV_ES;
> data.tmr_address = tmr_pa;
> data.tmr_len = SEV_ES_TMR_SIZE;
> }
> + return __sev_do_cmd_locked(SEV_CMD_INIT_EX, &data, error);
> +}
> +
> +static int __sev_platform_init_locked(int *error)
> +{
> + struct psp_device *psp = psp_master;
> + struct sev_device *sev;
> + int rc;
> + int (*init_function)(int *error) = sev_init_ex_nv_address ?
> + __sev_init_ex_locked :
> + __sev_init_locked;
> +
> + if (!psp || !psp->sev_data)
> + return -ENODEV;
> +
> + sev = psp->sev_data;
>
> - rc = __sev_do_cmd_locked(SEV_CMD_INIT, &data, error);
> + if (sev->state == SEV_STATE_INIT)
> + return 0;
> +
> + rc = init_function(error);
> if (rc && *error == SEV_RET_SECURE_DATA_INVALID) {
> /*
> * INIT command returned an integrity check failure
> @@ -290,8 +427,8 @@ static int __sev_platform_init_locked(int *error)
> * failed and persistent state has been erased.
> * Retrying INIT command here should succeed.
> */
> - dev_dbg(sev->dev, "SEV: retrying INIT command");
> - rc = __sev_do_cmd_locked(SEV_CMD_INIT, &data, error);
> + dev_err(sev->dev, "SEV: retrying INIT command");
> + rc = init_function(error);
> }
>
> if (rc)
> @@ -307,7 +444,7 @@ static int __sev_platform_init_locked(int *error)
>
> dev_dbg(sev->dev, "SEV firmware initialized\n");
>
> - return rc;
> + return 0;
> }
>
> int sev_platform_init(int *error)
> @@ -987,7 +1124,7 @@ static int sev_misc_init(struct sev_device *sev)
>
> init_waitqueue_head(&sev->int_queue);
> sev->misc = misc_dev;
> - dev_dbg(dev, "registered SEV device\n");
> + dev_err(dev, "registered SEV device\n");
>
> return 0;
> }
> @@ -1061,6 +1198,12 @@ static void sev_firmware_shutdown(struct sev_device *sev)
> get_order(SEV_ES_TMR_SIZE));
> sev_es_tmr = NULL;
> }
> +
> + if (sev_init_ex_nv_address) {
> + free_pages((unsigned long)sev_init_ex_nv_address,
> + get_order(NV_LENGTH));
> + sev_init_ex_nv_address = NULL;
> + }
> }
>
> void sev_dev_destroy(struct psp_device *psp)
> @@ -1105,6 +1248,19 @@ void sev_pci_init(void)
> sev_update_firmware(sev->dev) == 0)
> sev_get_api_version();
>
> + /* If an init_ex_path is provided rely on INIT_EX for PSP initialization
> + * instead of INIT.
> + */
> + if (init_ex_path) {
> + sev_init_ex_nv_address = sev_fw_alloc(NV_LENGTH);
> + if (!sev_init_ex_nv_address) {
> + dev_warn(
> + sev->dev,
> + "SEV: INIT_EX NV storage allocation failed, INIT-EX support unavailable\n");
> + goto err;
> + }
> + }
> +
> /* Obtain the TMR memory area for SEV-ES use */
> sev_es_tmr = sev_fw_alloc(SEV_ES_TMR_SIZE);
> if (!sev_es_tmr)
> diff --git a/include/linux/psp-sev.h b/include/linux/psp-sev.h
> index d48a7192e881..1595088c428b 100644
> --- a/include/linux/psp-sev.h
> +++ b/include/linux/psp-sev.h
> @@ -52,6 +52,7 @@ enum sev_cmd {
> SEV_CMD_DF_FLUSH = 0x00A,
> SEV_CMD_DOWNLOAD_FIRMWARE = 0x00B,
> SEV_CMD_GET_ID = 0x00C,
> + SEV_CMD_INIT_EX = 0x00D,
>
> /* Guest commands */
> SEV_CMD_DECOMMISSION = 0x020,
> @@ -102,6 +103,26 @@ struct sev_data_init {
> u32 tmr_len; /* In */
> } __packed;
>
> +/**
> + * struct sev_data_init_ex - INIT_EX command parameters
> + *
> + * @length: len of the command buffer read by the PSP
> + * @flags: processing flags
> + * @tmr_address: system physical address used for SEV-ES
> + * @tmr_len: len of tmr_address
> + * @nv_address: system physical address used for PSP NV storage
> + * @nv_len: len of nv_address
> + */
> +struct sev_data_init_ex {
> + u32 length; /* In */
> + u32 flags; /* In */
> + u64 tmr_address; /* In */
> + u32 tmr_len; /* In */
> + u32 reserved; /* In */
> + u64 nv_address; /* In/Out */
> + u32 nv_len; /* In */
> +} __packed;
> +
> #define SEV_INIT_FLAGS_SEV_ES 0x01
>
> /**
> --
> 2.33.1.1089.g2158813163f-goog
>
Reviewed-by: Marc Orr <marcorr@...gle.com>
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