[v2] sev-snp: parse MP tables for VMware hypervisor

[PATCH v2] sev-snp: parse MP tables for VMware hypervisor

Posted by Ajay Kaher 9 months, 1 week ago

For VMware hypervisor, SEV-SNP enabled VM's could boot without UEFI.
In this case, mpparse_find_mptable() has to be called to parse MP
tables which contains boot information.

Fixes: 0f4a1e80989a ("x86/sev: Skip ROM range scans and validation for SEV-SNP guests")
Co-developed-by: Ye Li <ye.li@broadcom.com>
Signed-off-by: Ye Li <ye.li@broadcom.com>
Signed-off-by: Ajay Kaher <ajay.kaher@broadcom.com>
Tested-by: Ye Li <ye.li@broadcom.com>
Reviewed-by: Kevin Loughlin <kevinloughlin@google.com>
---
Changes since v1:
https://lore.kernel.org/lkml/20241219114400.858980-1-ajay.kaher@broadcom.com/
        - use cc_platform_has(CC_ATTR_GUEST_SEV_SNP) instead of
          (sev_status & MSR_AMD64_SEV_SNP_ENABLED)
	- remove unwanted header files
---
 arch/x86/kernel/cpu/vmware.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/arch/x86/kernel/cpu/vmware.c b/arch/x86/kernel/cpu/vmware.c
index 00189cdeb..cb3f900c4 100644
--- a/arch/x86/kernel/cpu/vmware.c
+++ b/arch/x86/kernel/cpu/vmware.c
@@ -26,6 +26,7 @@
 #include <linux/export.h>
 #include <linux/clocksource.h>
 #include <linux/cpu.h>
+#include <linux/efi.h>
 #include <linux/reboot.h>
 #include <linux/static_call.h>
 #include <asm/div64.h>
@@ -429,6 +430,9 @@ static void __init vmware_platform_setup(void)
 		pr_warn("Failed to get TSC freq from the hypervisor\n");
 	}
 
+	if (cc_platform_has(CC_ATTR_GUEST_SEV_SNP) && !efi_enabled(EFI_BOOT))
+		x86_init.mpparse.find_mptable = mpparse_find_mptable;
+
 	vmware_paravirt_ops_setup();
 
 #ifdef CONFIG_X86_IO_APIC
-- 
2.39.4

Re: [PATCH v2] sev-snp: parse MP tables for VMware hypervisor

Posted by Borislav Petkov 9 months, 1 week ago

On Thu, Mar 13, 2025 at 05:31:11PM +0000, Ajay Kaher wrote:
> For VMware hypervisor, SEV-SNP enabled VM's could boot without UEFI.

VMs

mingo, pls fix up while applying.

> In this case, mpparse_find_mptable() has to be called to parse MP
> tables which contains boot information.
> 
> Fixes: 0f4a1e80989a ("x86/sev: Skip ROM range scans and validation for SEV-SNP guests")
> Co-developed-by: Ye Li <ye.li@broadcom.com>
> Signed-off-by: Ye Li <ye.li@broadcom.com>
> Signed-off-by: Ajay Kaher <ajay.kaher@broadcom.com>
> Tested-by: Ye Li <ye.li@broadcom.com>
> Reviewed-by: Kevin Loughlin <kevinloughlin@google.com>
> ---
> Changes since v1:
> https://lore.kernel.org/lkml/20241219114400.858980-1-ajay.kaher@broadcom.com/
>         - use cc_platform_has(CC_ATTR_GUEST_SEV_SNP) instead of
>           (sev_status & MSR_AMD64_SEV_SNP_ENABLED)
> 	- remove unwanted header files
> ---
>  arch/x86/kernel/cpu/vmware.c | 4 ++++
>  1 file changed, 4 insertions(+)

Acked-by: Borislav Petkov (AMD) <bp@alien8.de>

-- 
Regards/Gruss,
    Boris.

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

[tip: x86/urgent] x86/vmware: Parse MP tables for SEV-SNP enabled guests under VMware hypervisors

Posted by tip-bot2 for Ajay Kaher 9 months, 1 week ago

The following commit has been merged into the x86/urgent branch of tip:

Commit-ID:     a2ab25529bbcea51b5e01dded79f45aeb94f644a
Gitweb:        https://git.kernel.org/tip/a2ab25529bbcea51b5e01dded79f45aeb94f644a
Author:        Ajay Kaher <ajay.kaher@broadcom.com>
AuthorDate:    Thu, 13 Mar 2025 17:31:11 
Committer:     Ingo Molnar <mingo@kernel.org>
CommitterDate: Thu, 13 Mar 2025 19:01:09 +01:00

x86/vmware: Parse MP tables for SEV-SNP enabled guests under VMware hypervisors

Under VMware hypervisors, SEV-SNP enabled VMs are fundamentally able to boot
without UEFI, but this regressed a year ago due to:

  0f4a1e80989a ("x86/sev: Skip ROM range scans and validation for SEV-SNP guests")

In this case, mpparse_find_mptable() has to be called to parse MP
tables which contains the necessary boot information.

[ mingo: Updated the changelog. ]

Fixes: 0f4a1e80989a ("x86/sev: Skip ROM range scans and validation for SEV-SNP guests")
Co-developed-by: Ye Li <ye.li@broadcom.com>
Signed-off-by: Ye Li <ye.li@broadcom.com>
Signed-off-by: Ajay Kaher <ajay.kaher@broadcom.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Tested-by: Ye Li <ye.li@broadcom.com>
Reviewed-by: Kevin Loughlin <kevinloughlin@google.com>
Acked-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/20250313173111.10918-1-ajay.kaher@broadcom.com
---
 arch/x86/kernel/cpu/vmware.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/arch/x86/kernel/cpu/vmware.c b/arch/x86/kernel/cpu/vmware.c
index 00189cd..cb3f900 100644
--- a/arch/x86/kernel/cpu/vmware.c
+++ b/arch/x86/kernel/cpu/vmware.c
@@ -26,6 +26,7 @@
 #include <linux/export.h>
 #include <linux/clocksource.h>
 #include <linux/cpu.h>
+#include <linux/efi.h>
 #include <linux/reboot.h>
 #include <linux/static_call.h>
 #include <asm/div64.h>
@@ -429,6 +430,9 @@ static void __init vmware_platform_setup(void)
 		pr_warn("Failed to get TSC freq from the hypervisor\n");
 	}
 
+	if (cc_platform_has(CC_ATTR_GUEST_SEV_SNP) && !efi_enabled(EFI_BOOT))
+		x86_init.mpparse.find_mptable = mpparse_find_mptable;
+
 	vmware_paravirt_ops_setup();
 
 #ifdef CONFIG_X86_IO_APIC