Message-ID: <20180510172813.GD15817@pd.tnic>
Date:   Thu, 10 May 2018 19:28:13 +0200
From:   Borislav Petkov <bp@...e.de>
To:     Janakarajan Natarajan <Janakarajan.Natarajan@....com>
Cc:     linux-crypto@...r.kernel.org, linux-kernel@...r.kernel.org,
        Tom Lendacky <thomas.lendacky@....com>,
        Gary Hook <gary.hook@....com>,
        Herbert Xu <herbert@...dor.apana.org.au>,
        "David S . Miller" <davem@...emloft.net>,
        Brijesh Singh <brijesh.singh@....com>,
        Paolo Bonzini <pbonzini@...hat.com>
Subject: Re: [PATCH RESEND 1/2] Add DOWNLOAD_FIRMWARE SEV command

Use a prefix for the subject pls:

Subject: [PATCH RESEND 1/2] crypto: ccp: Add DOWNLOAD_FIRMWARE SEV command

or 

Subject: [PATCH RESEND 1/2] crypto/ccp: Add DOWNLOAD_FIRMWARE SEV command

or so.

On Wed, May 09, 2018 at 11:18:27AM -0500, Janakarajan Natarajan wrote:
> The DOWNLOAD_FIRMWARE command, added as of SEV API v0.15, allows the OS
> to install SEV firmware newer than the currently active SEV firmware.
> 
> For the new SEV firmware to be applied it must:
> * Pass the validation test performed by the existing firmware.
> * Be of the same build or a newer build compared to the existing firmware.
> 
> For more information please refer to "Section 5.11 DOWNLOAD_FIRMWARE" of
> https://support.amd.com/TechDocs/55766_SEV-KM%20API_Specification.pdf
> 
> Signed-off-by: Janakarajan Natarajan <Janakarajan.Natarajan@....com>
> ---
>  drivers/crypto/ccp/psp-dev.c | 96 +++++++++++++++++++++++++++++++++++++++-----
>  drivers/crypto/ccp/psp-dev.h |  4 ++
>  include/linux/psp-sev.h      | 12 ++++++
>  3 files changed, 102 insertions(+), 10 deletions(-)
> 
> diff --git a/drivers/crypto/ccp/psp-dev.c b/drivers/crypto/ccp/psp-dev.c
> index d95ec52..1c78a2e 100644
> --- a/drivers/crypto/ccp/psp-dev.c
> +++ b/drivers/crypto/ccp/psp-dev.c
> @@ -22,11 +22,17 @@
>  #include <linux/delay.h>
>  #include <linux/hw_random.h>
>  #include <linux/ccp.h>
> +#include <linux/firmware.h>
>  
>  #include "sp-dev.h"
>  #include "psp-dev.h"
>  
> +#define SEV_VERSION_CHECK(_maj, _min)			\
> +		((psp_master->api_major) >= _maj &&	\
> +		 (psp_master->api_minor) >= _min)
> +
>  #define DEVICE_NAME	"sev"
> +#define SEV_FW_FILE	"amd-sev.fw"

Can we put this firmware in an amd folder like

	amd/sev.fw

or so, like we to with the microcode?

/lib/firmware/amd-ucode/
├── microcode_amd.bin
├── microcode_amd.bin.asc
├── microcode_amd_fam15h.bin
├── microcode_amd_fam15h.bin.asc
├── microcode_amd_fam16h.bin
└── microcode_amd_fam16h.bin.asc

It is tidier this way in the fw directory.

>  static DEFINE_MUTEX(sev_cmd_mutex);
>  static struct sev_misc_dev *misc_dev;
> @@ -112,6 +118,7 @@ static int sev_cmd_buffer_len(int cmd)
>  	case SEV_CMD_RECEIVE_UPDATE_DATA:	return sizeof(struct sev_data_receive_update_data);
>  	case SEV_CMD_RECEIVE_UPDATE_VMSA:	return sizeof(struct sev_data_receive_update_vmsa);
>  	case SEV_CMD_LAUNCH_UPDATE_SECRET:	return sizeof(struct sev_data_launch_secret);
> +	case SEV_CMD_DOWNLOAD_FIRMWARE:		return sizeof(struct sev_data_download_firmware);
>  	default:				return 0;
>  	}
>  
> @@ -378,6 +385,77 @@ void *psp_copy_user_blob(u64 __user uaddr, u32 len)
>  }
>  EXPORT_SYMBOL_GPL(psp_copy_user_blob);
>  
> +static int get_sev_api_version(void)

sev_get_api_version()

like the rest.

> +{
> +	struct sev_user_data_status *status;
> +	int error, ret;
> +
> +	status = &psp_master->status_cmd_buf;
> +	ret = sev_platform_status(status, &error);
> +	if (ret) {
> +		dev_err(psp_master->dev,
> +			"SEV: failed to get status. Error: %#x\n", error);
> +		return 1;
> +	}
> +
> +	psp_master->api_major = status->api_major;
> +	psp_master->api_minor = status->api_minor;
> +	psp_master->build = status->build;
> +
> +	return 0;
> +}
> +
> +/* Don't fail if SEV FW couldn't be updated. Continue with existing SEV FW */
> +static void sev_update_firmware(struct device *dev)
> +{
> +	struct sev_data_download_firmware *data;
> +	const struct firmware *firmware;
> +	int ret, error, order;
> +	struct page *p;
> +	u64 data_size;
> +
> +	ret = request_firmware(&firmware, SEV_FW_FILE, dev);
> +	if (ret < 0)
> +		return;
> +
> +	/*
> +	 * SEV FW expects the physical address given to it to be 32
> +	 * byte aligned. Memory allocated has structure placed at the
> +	 * beginning followed by the firmware being passed to the SEV
> +	 * FW. Allocate enough memory for data structure + alignment
> +	 * padding + SEV FW.
> +	 */
> +	data_size = ALIGN(sizeof(struct sev_data_download_firmware), 32);
> +
> +	order = get_order(firmware->size + data_size);
> +	p = alloc_pages(GFP_KERNEL, order);
> +	if (!p)
> +		goto fw_err;
> +
> +	/*
> +	 * Copy firmware data to a kernel allocated contiguous
> +	 * memory region.
> +	 */
> +	data = page_address(p);
> +	memcpy(page_address(p) + data_size, firmware->data, firmware->size);
> +
> +	data->address = __psp_pa(page_address(p) + data_size);
> +	data->len = firmware->size;
> +
> +	ret = sev_do_cmd(SEV_CMD_DOWNLOAD_FIRMWARE, data, &error);
> +	if (ret) {
> +		dev_dbg(dev, "Failed to update SEV firmware: %#x\n", error);
> +	} else {
> +		dev_info(dev, "SEV firmware update successful\n");
> +		get_sev_api_version();

Call that function in the caller of sev_update_firmware() and in its
success path. For that, make sev_update_firmware() return success/error
value.

> +	}
> +
> +	__free_pages(p, order);
> +
> +fw_err:
> +	release_firmware(firmware);
> +}
> +
>  static int sev_ioctl_do_pek_import(struct sev_issue_cmd *argp)
>  {
>  	struct sev_user_data_pek_cert_import input;
> @@ -750,7 +828,6 @@ EXPORT_SYMBOL_GPL(sev_issue_cmd_external_user);
>  
>  void psp_pci_init(void)
>  {
> -	struct sev_user_data_status *status;
>  	struct sp_device *sp;
>  	int error, rc;
>  
> @@ -760,6 +837,12 @@ void psp_pci_init(void)
>  
>  	psp_master = sp->psp_data;
>  
> +	if (get_sev_api_version())
> +		goto err;
> +
> +	if (SEV_VERSION_CHECK(0, 15))

That macro could use a readability improvement. This way it doesn't tell
me what the check is doing. Is it checking whether the version should be
0.15 or should it be bigger than 0.15 or what...?

I have to go look at its definition.

> +		sev_update_firmware(psp_master->dev);

I wonder if we should try to load a new fw *every* time we init the
driver. I guess so... can't think of something speaking against it right
now...

> +
>  	/* Initialize the platform */
>  	rc = sev_platform_init(&error);
>  	if (rc) {
> @@ -767,16 +850,9 @@ void psp_pci_init(void)
>  		goto err;
>  	}
>  
> -	/* Display SEV firmware version */
> -	status = &psp_master->status_cmd_buf;
> -	rc = sev_platform_status(status, &error);
> -	if (rc) {
> -		dev_err(sp->dev, "SEV: failed to get status error %#x\n", error);
> -		goto err;
> -	}
> +	dev_info(sp->dev, "SEV API:%d.%d build:%d\n", psp_master->api_major,
> +		 psp_master->api_minor, psp_master->build);
>  
> -	dev_info(sp->dev, "SEV API:%d.%d build:%d\n", status->api_major,
> -		 status->api_minor, status->build);
>  	return;
>  
>  err:

But, before we do further games with this, I'm able to trigger the
following link error with the attached config. So pls sort that out
first. The idea is that the user should not be able to create a failing
config.

arch/x86/kvm/svm.o: In function `__sev_issue_cmd':
/home/boris/kernel/linux/arch/x86/kvm/svm.c:6256: undefined reference to `sev_issue_cmd_external_user'
arch/x86/kvm/svm.o: In function `sev_unbind_asid':
/home/boris/kernel/linux/arch/x86/kvm/svm.c:1740: undefined reference to `sev_guest_deactivate'
/home/boris/kernel/linux/arch/x86/kvm/svm.c:1743: undefined reference to `sev_guest_df_flush'
/home/boris/kernel/linux/arch/x86/kvm/svm.c:1752: undefined reference to `sev_guest_decommission'
arch/x86/kvm/svm.o: In function `sev_guest_init':
/home/boris/kernel/linux/arch/x86/kvm/svm.c:6207: undefined reference to `sev_platform_init'
arch/x86/kvm/svm.o: In function `sev_launch_start':
/home/boris/kernel/linux/arch/x86/kvm/svm.c:6302: undefined reference to `psp_copy_user_blob'
/home/boris/kernel/linux/arch/x86/kvm/svm.c:6290: undefined reference to `psp_copy_user_blob'
arch/x86/kvm/svm.o: In function `sev_bind_asid':
/home/boris/kernel/linux/arch/x86/kvm/svm.c:6230: undefined reference to `sev_guest_df_flush'
/home/boris/kernel/linux/arch/x86/kvm/svm.c:6241: undefined reference to `sev_guest_activate'
arch/x86/kvm/svm.o: In function `sev_launch_secret':
/home/boris/kernel/linux/arch/x86/kvm/svm.c:6833: undefined reference to `psp_copy_user_blob'
/home/boris/kernel/linux/arch/x86/kvm/svm.c:6842: undefined reference to `psp_copy_user_blob'
arch/x86/kvm/svm.o: In function `sev_hardware_setup':
/home/boris/kernel/linux/arch/x86/kvm/svm.c:1237: undefined reference to `sev_platform_status'
make: *** [vmlinux] Error 1

Thx.

-- 
Regards/Gruss,
    Boris.

SUSE Linux GmbH, GF: Felix Imendörffer, Jane Smithard, Graham Norton, HRB 21284 (AG Nürnberg)
-- 

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