| Message ID | 20231230161954.569267-2-michael.roth@amd.com (mailing list archive) |
|---|---|
| State | Not Applicable |
| Delegated to: | Herbert Xu |
| Headers | show |
| Series | Add AMD Secure Nested Paging (SEV-SNP) Initialization Support | expand |
On Sat, Dec 30, 2023 at 10:19:29AM -0600, Michael Roth wrote: > From: Brijesh Singh <brijesh.singh@amd.com> > > Add CPU feature detection for Secure Encrypted Virtualization with > Secure Nested Paging. This feature adds a strong memory integrity > protection to help prevent malicious hypervisor-based attacks like > data replay, memory re-mapping, and more. > > Since enabling the SNP CPU feature imposes a number of additional > requirements on host initialization and handling legacy firmware APIs > for SEV/SEV-ES guests, only introduce the CPU feature bit so that the > relevant handling can be added, but leave it disabled via a > disabled-features mask. > > Once all the necessary changes needed to maintain legacy SEV/SEV-ES > support are introduced in subsequent patches, the SNP feature bit will > be unmasked/enabled. > > Signed-off-by: Brijesh Singh <brijesh.singh@amd.com> > Signed-off-by: Jarkko Sakkinen <jarkko@profian.com> > Signed-off-by: Ashish Kalra <Ashish.Kalra@amd.com> > Signed-off-by: Michael Roth <michael.roth@amd.com> > --- > arch/x86/include/asm/cpufeatures.h | 1 + > arch/x86/include/asm/disabled-features.h | 4 +++- > arch/x86/kernel/cpu/amd.c | 5 +++-- > tools/arch/x86/include/asm/cpufeatures.h | 1 + > 4 files changed, 8 insertions(+), 3 deletions(-) > > diff --git a/arch/x86/include/asm/cpufeatures.h b/arch/x86/include/asm/cpufeatures.h > index 29cb275a219d..9492dcad560d 100644 > --- a/arch/x86/include/asm/cpufeatures.h > +++ b/arch/x86/include/asm/cpufeatures.h > @@ -442,6 +442,7 @@ > #define X86_FEATURE_SEV (19*32+ 1) /* AMD Secure Encrypted Virtualization */ > #define X86_FEATURE_VM_PAGE_FLUSH (19*32+ 2) /* "" VM Page Flush MSR is supported */ > #define X86_FEATURE_SEV_ES (19*32+ 3) /* AMD Secure Encrypted Virtualization - Encrypted State */ > +#define X86_FEATURE_SEV_SNP (19*32+ 4) /* AMD Secure Encrypted Virtualization - Secure Nested Paging */ > #define X86_FEATURE_V_TSC_AUX (19*32+ 9) /* "" Virtual TSC_AUX */ > #define X86_FEATURE_SME_COHERENT (19*32+10) /* "" AMD hardware-enforced cache coherency */ > #define X86_FEATURE_DEBUG_SWAP (19*32+14) /* AMD SEV-ES full debug state swap support */ > diff --git a/arch/x86/include/asm/disabled-features.h b/arch/x86/include/asm/disabled-features.h > index 702d93fdd10e..a864a5b208fa 100644 > --- a/arch/x86/include/asm/disabled-features.h > +++ b/arch/x86/include/asm/disabled-features.h > @@ -117,6 +117,8 @@ > #define DISABLE_IBT (1 << (X86_FEATURE_IBT & 31)) > #endif > > +#define DISABLE_SEV_SNP 0 I think you want this here if SEV_SNP should be initially disabled: diff --git a/arch/x86/include/asm/disabled-features.h b/arch/x86/include/asm/disabled-features.h index a864a5b208fa..5b2fab8ad262 100644 --- a/arch/x86/include/asm/disabled-features.h +++ b/arch/x86/include/asm/disabled-features.h @@ -117,7 +117,7 @@ #define DISABLE_IBT (1 << (X86_FEATURE_IBT & 31)) #endif -#define DISABLE_SEV_SNP 0 +#define DISABLE_SEV_SNP (1 << (X86_FEATURE_SEV_SNP & 31)) /* * Make sure to add features to the correct mask
On Sun, Dec 31, 2023 at 12:50:12PM +0100, Borislav Petkov wrote: > On Sat, Dec 30, 2023 at 10:19:29AM -0600, Michael Roth wrote: > > From: Brijesh Singh <brijesh.singh@amd.com> > > > > Add CPU feature detection for Secure Encrypted Virtualization with > > Secure Nested Paging. This feature adds a strong memory integrity > > protection to help prevent malicious hypervisor-based attacks like > > data replay, memory re-mapping, and more. > > > > Since enabling the SNP CPU feature imposes a number of additional > > requirements on host initialization and handling legacy firmware APIs > > for SEV/SEV-ES guests, only introduce the CPU feature bit so that the > > relevant handling can be added, but leave it disabled via a > > disabled-features mask. > > > > Once all the necessary changes needed to maintain legacy SEV/SEV-ES > > support are introduced in subsequent patches, the SNP feature bit will > > be unmasked/enabled. > > > > Signed-off-by: Brijesh Singh <brijesh.singh@amd.com> > > Signed-off-by: Jarkko Sakkinen <jarkko@profian.com> > > Signed-off-by: Ashish Kalra <Ashish.Kalra@amd.com> > > Signed-off-by: Michael Roth <michael.roth@amd.com> > > --- > > arch/x86/include/asm/cpufeatures.h | 1 + > > arch/x86/include/asm/disabled-features.h | 4 +++- > > arch/x86/kernel/cpu/amd.c | 5 +++-- > > tools/arch/x86/include/asm/cpufeatures.h | 1 + > > 4 files changed, 8 insertions(+), 3 deletions(-) > > > > diff --git a/arch/x86/include/asm/cpufeatures.h b/arch/x86/include/asm/cpufeatures.h > > index 29cb275a219d..9492dcad560d 100644 > > --- a/arch/x86/include/asm/cpufeatures.h > > +++ b/arch/x86/include/asm/cpufeatures.h > > @@ -442,6 +442,7 @@ > > #define X86_FEATURE_SEV (19*32+ 1) /* AMD Secure Encrypted Virtualization */ > > #define X86_FEATURE_VM_PAGE_FLUSH (19*32+ 2) /* "" VM Page Flush MSR is supported */ > > #define X86_FEATURE_SEV_ES (19*32+ 3) /* AMD Secure Encrypted Virtualization - Encrypted State */ > > +#define X86_FEATURE_SEV_SNP (19*32+ 4) /* AMD Secure Encrypted Virtualization - Secure Nested Paging */ > > #define X86_FEATURE_V_TSC_AUX (19*32+ 9) /* "" Virtual TSC_AUX */ > > #define X86_FEATURE_SME_COHERENT (19*32+10) /* "" AMD hardware-enforced cache coherency */ > > #define X86_FEATURE_DEBUG_SWAP (19*32+14) /* AMD SEV-ES full debug state swap support */ > > diff --git a/arch/x86/include/asm/disabled-features.h b/arch/x86/include/asm/disabled-features.h > > index 702d93fdd10e..a864a5b208fa 100644 > > --- a/arch/x86/include/asm/disabled-features.h > > +++ b/arch/x86/include/asm/disabled-features.h > > @@ -117,6 +117,8 @@ > > #define DISABLE_IBT (1 << (X86_FEATURE_IBT & 31)) > > #endif > > > > +#define DISABLE_SEV_SNP 0 > > I think you want this here if SEV_SNP should be initially disabled: > > diff --git a/arch/x86/include/asm/disabled-features.h b/arch/x86/include/asm/disabled-features.h > index a864a5b208fa..5b2fab8ad262 100644 > --- a/arch/x86/include/asm/disabled-features.h > +++ b/arch/x86/include/asm/disabled-features.h > @@ -117,7 +117,7 @@ > #define DISABLE_IBT (1 << (X86_FEATURE_IBT & 31)) > #endif > > -#define DISABLE_SEV_SNP 0 > +#define DISABLE_SEV_SNP (1 << (X86_FEATURE_SEV_SNP & 31)) > > /* > * Make sure to add features to the correct mask Sorry, I must have inverted things when I was squashing in the changes =\ I've gone ahead and force-pushed your fixup to the snp-host-init-v1 branch. Thanks, Mike > > -- > Regards/Gruss, > Boris. > > https://people.kernel.org/tglx/notes-about-netiquette
diff --git a/arch/x86/include/asm/cpufeatures.h b/arch/x86/include/asm/cpufeatures.h index 29cb275a219d..9492dcad560d 100644 --- a/arch/x86/include/asm/cpufeatures.h +++ b/arch/x86/include/asm/cpufeatures.h @@ -442,6 +442,7 @@ #define X86_FEATURE_SEV (19*32+ 1) /* AMD Secure Encrypted Virtualization */ #define X86_FEATURE_VM_PAGE_FLUSH (19*32+ 2) /* "" VM Page Flush MSR is supported */ #define X86_FEATURE_SEV_ES (19*32+ 3) /* AMD Secure Encrypted Virtualization - Encrypted State */ +#define X86_FEATURE_SEV_SNP (19*32+ 4) /* AMD Secure Encrypted Virtualization - Secure Nested Paging */ #define X86_FEATURE_V_TSC_AUX (19*32+ 9) /* "" Virtual TSC_AUX */ #define X86_FEATURE_SME_COHERENT (19*32+10) /* "" AMD hardware-enforced cache coherency */ #define X86_FEATURE_DEBUG_SWAP (19*32+14) /* AMD SEV-ES full debug state swap support */ diff --git a/arch/x86/include/asm/disabled-features.h b/arch/x86/include/asm/disabled-features.h index 702d93fdd10e..a864a5b208fa 100644 --- a/arch/x86/include/asm/disabled-features.h +++ b/arch/x86/include/asm/disabled-features.h @@ -117,6 +117,8 @@ #define DISABLE_IBT (1 << (X86_FEATURE_IBT & 31)) #endif +#define DISABLE_SEV_SNP 0 + /* * Make sure to add features to the correct mask */ @@ -141,7 +143,7 @@ DISABLE_ENQCMD) #define DISABLED_MASK17 0 #define DISABLED_MASK18 (DISABLE_IBT) -#define DISABLED_MASK19 0 +#define DISABLED_MASK19 (DISABLE_SEV_SNP) #define DISABLED_MASK20 0 #define DISABLED_MASK_CHECK BUILD_BUG_ON_ZERO(NCAPINTS != 21) diff --git a/arch/x86/kernel/cpu/amd.c b/arch/x86/kernel/cpu/amd.c index 9f42d1c59e09..9a17165dfe84 100644 --- a/arch/x86/kernel/cpu/amd.c +++ b/arch/x86/kernel/cpu/amd.c @@ -592,8 +592,8 @@ static void early_detect_mem_encrypt(struct cpuinfo_x86 *c) * SME feature (set in scattered.c). * If the kernel has not enabled SME via any means then * don't advertise the SME feature. - * For SEV: If BIOS has not enabled SEV then don't advertise the - * SEV and SEV_ES feature (set in scattered.c). + * For SEV: If BIOS has not enabled SEV then don't advertise SEV and + * any additional functionality based on it. * * In all cases, since support for SME and SEV requires long mode, * don't advertise the feature under CONFIG_X86_32. @@ -628,6 +628,7 @@ static void early_detect_mem_encrypt(struct cpuinfo_x86 *c) clear_sev: setup_clear_cpu_cap(X86_FEATURE_SEV); setup_clear_cpu_cap(X86_FEATURE_SEV_ES); + setup_clear_cpu_cap(X86_FEATURE_SEV_SNP); } } diff --git a/tools/arch/x86/include/asm/cpufeatures.h b/tools/arch/x86/include/asm/cpufeatures.h index f4542d2718f4..e58bd69356ee 100644 --- a/tools/arch/x86/include/asm/cpufeatures.h +++ b/tools/arch/x86/include/asm/cpufeatures.h @@ -437,6 +437,7 @@ #define X86_FEATURE_SEV (19*32+ 1) /* AMD Secure Encrypted Virtualization */ #define X86_FEATURE_VM_PAGE_FLUSH (19*32+ 2) /* "" VM Page Flush MSR is supported */ #define X86_FEATURE_SEV_ES (19*32+ 3) /* AMD Secure Encrypted Virtualization - Encrypted State */ +#define X86_FEATURE_SEV_SNP (19*32+ 4) /* AMD Secure Encrypted Virtualization - Secure Nested Paging */ #define X86_FEATURE_V_TSC_AUX (19*32+ 9) /* "" Virtual TSC_AUX */ #define X86_FEATURE_SME_COHERENT (19*32+10) /* "" AMD hardware-enforced cache coherency */ #define X86_FEATURE_DEBUG_SWAP (19*32+14) /* AMD SEV-ES full debug state swap support */