Re: [PATCH v4 01/15] x86/sev: Shorten snp_secrets_page_layout to snp_secrets_page

From: Borislav Petkov
Date: Thu Apr 25 2024 - 09:32:06 EST


On Wed, Apr 24, 2024 at 10:57:57AM -0500, Tom Lendacky wrote:
> diff --git a/arch/x86/kernel/sev.c b/arch/x86/kernel/sev.c
> index 995f94467101..6949fbccec40 100644
> --- a/arch/x86/kernel/sev.c
> +++ b/arch/x86/kernel/sev.c
> @@ -648,7 +648,7 @@ static u64 __init get_secrets_page(void)
>
> static u64 __init get_snp_jump_table_addr(void)
> {
> - struct snp_secrets_page_layout *layout;
> + struct snp_secrets_page *layout;

Yes, and I'd go change that "layout" name to "secrets" too because
layout doesn't make any sense when talking about a secrets page.

This, OTOH:

addr = secrets->os_area.ap_jump_table_pa;

means something: the address comes from the secrets page. Not from the
"layout". :-)

IOW, diff ontop:

diff --git a/arch/x86/kernel/sev.c b/arch/x86/kernel/sev.c
index 25056346bc18..790e4818f7c6 100644
--- a/arch/x86/kernel/sev.c
+++ b/arch/x86/kernel/sev.c
@@ -648,7 +648,7 @@ static u64 __init get_secrets_page(void)

static u64 __init get_snp_jump_table_addr(void)
{
- struct snp_secrets_page *layout;
+ struct snp_secrets_page *secrets;
void __iomem *mem;
u64 pa, addr;

@@ -662,9 +662,9 @@ static u64 __init get_snp_jump_table_addr(void)
return 0;
}

- layout = (__force struct snp_secrets_page *)mem;
+ secrets = (__force struct snp_secrets_page *)mem;

- addr = layout->os_area.ap_jump_table_pa;
+ addr = secrets->os_area.ap_jump_table_pa;
iounmap(mem);

return addr;
diff --git a/drivers/virt/coco/sev-guest/sev-guest.c b/drivers/virt/coco/sev-guest/sev-guest.c
index 04a7bd1e4314..654290a8e1ba 100644
--- a/drivers/virt/coco/sev-guest/sev-guest.c
+++ b/drivers/virt/coco/sev-guest/sev-guest.c
@@ -59,7 +59,7 @@ struct snp_guest_dev {
*/
struct snp_guest_msg secret_request, secret_response;

- struct snp_secrets_page *layout;
+ struct snp_secrets_page *secrets;
struct snp_req_data input;
union {
struct snp_report_req report;
@@ -743,26 +743,26 @@ static const struct file_operations snp_guest_fops = {
.unlocked_ioctl = snp_guest_ioctl,
};

-static u8 *get_vmpck(int id, struct snp_secrets_page *layout, u32 **seqno)
+static u8 *get_vmpck(int id, struct snp_secrets_page *secrets, u32 **seqno)
{
u8 *key = NULL;

switch (id) {
case 0:
- *seqno = &layout->os_area.msg_seqno_0;
- key = layout->vmpck0;
+ *seqno = &secrets->os_area.msg_seqno_0;
+ key = secrets->vmpck0;
break;
case 1:
- *seqno = &layout->os_area.msg_seqno_1;
- key = layout->vmpck1;
+ *seqno = &secrets->os_area.msg_seqno_1;
+ key = secrets->vmpck1;
break;
case 2:
- *seqno = &layout->os_area.msg_seqno_2;
- key = layout->vmpck2;
+ *seqno = &secrets->os_area.msg_seqno_2;
+ key = secrets->vmpck2;
break;
case 3:
- *seqno = &layout->os_area.msg_seqno_3;
- key = layout->vmpck3;
+ *seqno = &secrets->os_area.msg_seqno_3;
+ key = secrets->vmpck3;
break;
default:
break;
@@ -898,7 +898,7 @@ static void unregister_sev_tsm(void *data)
static int __init sev_guest_probe(struct platform_device *pdev)
{
struct sev_guest_platform_data *data;
- struct snp_secrets_page *layout;
+ struct snp_secrets_page *secrets;
struct device *dev = &pdev->dev;
struct snp_guest_dev *snp_dev;
struct miscdevice *misc;
@@ -916,7 +916,7 @@ static int __init sev_guest_probe(struct platform_device *pdev)
if (!mapping)
return -ENODEV;

- layout = (__force void *)mapping;
+ secrets = (__force void *)mapping;

ret = -ENOMEM;
snp_dev = devm_kzalloc(&pdev->dev, sizeof(struct snp_guest_dev), GFP_KERNEL);
@@ -924,7 +924,7 @@ static int __init sev_guest_probe(struct platform_device *pdev)
goto e_unmap;

ret = -EINVAL;
- snp_dev->vmpck = get_vmpck(vmpck_id, layout, &snp_dev->os_area_msg_seqno);
+ snp_dev->vmpck = get_vmpck(vmpck_id, secrets, &snp_dev->os_area_msg_seqno);
if (!snp_dev->vmpck) {
dev_err(dev, "invalid vmpck id %d\n", vmpck_id);
goto e_unmap;
@@ -938,7 +938,7 @@ static int __init sev_guest_probe(struct platform_device *pdev)

platform_set_drvdata(pdev, snp_dev);
snp_dev->dev = dev;
- snp_dev->layout = layout;
+ snp_dev->secrets = secrets;

/* Allocate the shared page used for the request and response message. */
snp_dev->request = alloc_shared_pages(dev, sizeof(struct snp_guest_msg));

--
Regards/Gruss,
Boris.

https://people.kernel.org/tglx/notes-about-netiquette