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Date: Fri, 29 Oct 2021 12:56:06 -0500
From: Tom Lendacky <thomas.lendacky@....com>
To: Peter Gonda <pgonda@...gle.com>,
"Relph, Richard" <Richard.Relph@....com>
Cc: David Rientjes <rientjes@...gle.com>,
Brijesh Singh <brijesh.singh@....com>,
Marc Orr <marcorr@...gle.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 10/29/21 12:26 PM, Peter Gonda wrote:
> On Fri, Oct 29, 2021 at 8:45 AM Tom Lendacky <thomas.lendacky@....com> wrote:
>>
>> On 10/28/21 12:57 PM, Peter Gonda 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.
>>
>> IIUC, it looks as though the file has to exist before the very first use,
>> otherwise the initialization will fail. Did you consider checking for the
>> presence of the file first and, if not there, just using a memory area of
>> all f's (as documented in the SEV API)? Then on successful INIT, the
>> memory would be written and the file created.
>
> Thats a great idea. I'll add that functionality.
It all depends on how you want to treat the absence of the file. I can see
use cases for both creating automatically or failing (e.g. there was a
typo in the path).
>
>>
>> Either way, probably worth adding to the commit message. And if you stay
>> with having to pre-allocate the file, it's worth adding to the SEV
>> documentation what is required to be done to initialize the file.
>>
>> Although, INIT_EX is probably worth adding to the SEV documentation in
>> general.
>
> Is this (https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.kernel.org%2Fdoc%2FDocumentation%2Fvirt%2Fkvm%2Famd-memory-encryption.rst&data=04%7C01%7CThomas.Lendacky%40amd.com%7Cd9723c44ea764cc7540e08d99b013bbb%7C3dd8961fe4884e608e11a82d994e183d%7C0%7C0%7C637711251880475091%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&sdata=WJtwak6F%2Bn7PC8R1ohsC%2FNKGi7oDWFTi72NJDteyQoM%3D&reserved=0)
> the documentation you were referring too? If so I can add another
> patch before this one to document INIT, then add the INIT_EX
> documentation here. Or were you thinking something else?
Yes, that's the documentation I was referring to. I think you can just add
something to the KVM_SEV_INIT entry that talks about the new module
parameter and a bit about the file and how that file will be used. If you
decide to stay with a pre-created file, some details about how to create
the file would then be appropriate.
Thanks,
Tom
>
>>
>>>
>>> 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)
>>
>> Just me, but I think '32 * 1024' would be a bit clearer.
>
> SGTM and more consistent with SEV_ES_TMR_SIZE.
>
>>
>>> +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);
>>
>> Maybe move this to just under the SEV_CMD_INIT: case statement?
>>
>>> 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);
>>
>> Add a blank line here.
>>
>>> + 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);
>>> + }
>>
>> Add a blank line here.
>>
>>> + 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");
>>
>> Add a blank line here.
>
> Added all these blank lines.
>
>>
>>> + 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,
>>
>> maybe say INIT(_EX)?
>
> Done.
>
>>
>>> + * PLATFORM_RESET, PEK_GEN, PEK_CERT_IMPORT, and
>>> + * PDH_GEN do.
>>
>> Does SHUTDOWN modify the SPI/NV area? Otherwise a separate comment about
>> why it is included below.
>
> Double checked the FW doc looks like it does not. Richard can you
> confirm? If it doesn't I'll remove this case.
>
> >
>>> + */
>>> + 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);
>>
>> You already have error messages in the sev_write_nv_memory() function,
>> this one probably isn't needed.
>
> Removed.
>
>>
>>> +}
>>> +
>>> 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;
>>
>> Inadvertant deletion?
>
> Oops only testing with SEV guests. Will test with ES too. Fixed.
>
>>
>>> data.tmr_address = tmr_pa;
>>> data.tmr_len = SEV_ES_TMR_SIZE;
>>> }
>>
>> Add a blank line here.
>>
>>> + 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;
>>
>> This seems a bit much in the declaration. How about moving the assignment
>> down to just before the first call?
>
> Done.
>
>>
>>> +
>>> + 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");
>>
>> Maybe dev_notice() instead of dev_err()?
>
> Done.,
>
>>
>>> + 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");
>>
>> Not sure this is a necessary change... but, if you don't want this as a
>> dev_dbg() then it should be a dev_info(), because it is not an error.
>
> Oops this was my debugging. Reverted.
>
>>
>>>
>>> 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(
>>
>> Shouldn't this be a dev_err(), since you are erroring out?
>>
>>> + sev->dev,
>>
>> Move this up to the previous line, i.e.: dev_err(sev->dev,
>>
>>> + "SEV: INIT_EX NV storage allocation failed, INIT-EX support unavailable\n");
>>
>> Since you're erroring out, probably enough to just have the first part of
>> that message. But if not:
>>
>> s/INIT-EX/INIT_EX/
>
> Fixed this log line.
>
>>
>> Thanks,
>> Tom
>>
>>> + 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
>>>
>>> /**
>>>
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