* [PATCH v6 0/2] nosnp sev command line support
@ 2024-10-10 12:14 Pavan Kumar Paluri
2024-10-10 12:14 ` [PATCH v6 1/2] x86, KVM:SVM: Move sev specific parsing into arch/x86/virt/svm Pavan Kumar Paluri
2024-10-10 12:14 ` [PATCH v6 2/2] x86 KVM:SVM: Provide "nosnp" boot option for sev kernel command line Pavan Kumar Paluri
0 siblings, 2 replies; 10+ messages in thread
From: Pavan Kumar Paluri @ 2024-10-10 12:14 UTC (permalink / raw)
To: linux-kernel
Cc: linux-doc, linux-coco, Borislav Petkov, Thomas Gleixner,
Ingo Molnar, Dave Hansen, Eric Van Tassell, Tom Lendacky,
Ashish Kalra, Michael Roth, H . Peter Anvin, Peter Zijlstra,
Pavan Kumar Paluri, Dhaval Giani
Provide "nosnp" boot option via "sev=nosnp" kernel command line to
prevent SEV-SNP [1] capable host kernel from enabling SEV-SNP and
initializing Reverse Map Table (RMP)
Setting 'nosnp' avoids the RMP check overhead in memory accesses when
users do not want to run SEV-SNP guests.
On providing sev=nosnp via kernel command line:
cat /sys/module/kvm_amd/parameters/sev_snp should be "N".
The patchset is based on tip/master.
Reference:
[1] https://www.amd.com/content/dam/amd/en/documents/processor-tech-docs/programmer-references/24593.pdf
Changelog:
=========
v5:
* Update cover-letter and Documentation to include information on why
nosnp command line option is required (Dave Hansen)
* Remove <asm/cache.h> stray header introduced in the previous
versions because of __read_mostly attribute that is now moved into
virt/svm/cmdline.c
* Link: https://lore.kernel.org/all/20240930231102.123403-1-papaluri@amd.com/
v4:
* Move __read_mostly attribute to place where sev_cfg is declared (Tom)
* Link: https://lore.kernel.org/all/20240922033626.29038-1-papaluri@amd.com/
Pavan Kumar Paluri (2):
x86, KVM:SVM: Move sev specific parsing into arch/x86/virt/svm
x86 KVM:SVM: Provide "nosnp" boot option for sev kernel command line
.../arch/x86/x86_64/boot-options.rst | 5 +++
arch/x86/coco/sev/core.c | 44 -------------------
arch/x86/include/asm/sev-common.h | 27 ++++++++++++
arch/x86/virt/svm/Makefile | 1 +
arch/x86/virt/svm/cmdline.c | 39 ++++++++++++++++
5 files changed, 72 insertions(+), 44 deletions(-)
create mode 100644 arch/x86/virt/svm/cmdline.c
base-commit: 00d91979d23c88d3f50870e22fc9cec3f5e26a2a
--
2.34.1
^ permalink raw reply [flat|nested] 10+ messages in thread* [PATCH v6 1/2] x86, KVM:SVM: Move sev specific parsing into arch/x86/virt/svm 2024-10-10 12:14 [PATCH v6 0/2] nosnp sev command line support Pavan Kumar Paluri @ 2024-10-10 12:14 ` Pavan Kumar Paluri 2024-10-11 16:21 ` Borislav Petkov 2024-10-10 12:14 ` [PATCH v6 2/2] x86 KVM:SVM: Provide "nosnp" boot option for sev kernel command line Pavan Kumar Paluri 1 sibling, 1 reply; 10+ messages in thread From: Pavan Kumar Paluri @ 2024-10-10 12:14 UTC (permalink / raw) To: linux-kernel Cc: linux-doc, linux-coco, Borislav Petkov, Thomas Gleixner, Ingo Molnar, Dave Hansen, Eric Van Tassell, Tom Lendacky, Ashish Kalra, Michael Roth, H . Peter Anvin, Peter Zijlstra, Pavan Kumar Paluri, Dhaval Giani Move SEV specific kernel command line option parsing support from arch/x86/coco/sev/core.c to arch/x86/virt/svm/cmdline.c so that both host and guest related SEV command line options can be supported. No functional changes intended. Signed-off-by: Pavan Kumar Paluri <papaluri@amd.com> Reviewed-by: Tom Lendacky <thomas.lendacky@amd.com> --- arch/x86/coco/sev/core.c | 44 ------------------------------- arch/x86/include/asm/sev-common.h | 27 +++++++++++++++++++ arch/x86/virt/svm/Makefile | 1 + arch/x86/virt/svm/cmdline.c | 32 ++++++++++++++++++++++ 4 files changed, 60 insertions(+), 44 deletions(-) create mode 100644 arch/x86/virt/svm/cmdline.c diff --git a/arch/x86/coco/sev/core.c b/arch/x86/coco/sev/core.c index de1df0cb45da..ff19e805e7a1 100644 --- a/arch/x86/coco/sev/core.c +++ b/arch/x86/coco/sev/core.c @@ -141,33 +141,6 @@ static DEFINE_PER_CPU(struct sev_es_save_area *, sev_vmsa); static DEFINE_PER_CPU(struct svsm_ca *, svsm_caa); static DEFINE_PER_CPU(u64, svsm_caa_pa); -struct sev_config { - __u64 debug : 1, - - /* - * Indicates when the per-CPU GHCB has been created and registered - * and thus can be used by the BSP instead of the early boot GHCB. - * - * For APs, the per-CPU GHCB is created before they are started - * and registered upon startup, so this flag can be used globally - * for the BSP and APs. - */ - ghcbs_initialized : 1, - - /* - * Indicates when the per-CPU SVSM CA is to be used instead of the - * boot SVSM CA. - * - * For APs, the per-CPU SVSM CA is created as part of the AP - * bringup, so this flag can be used globally for the BSP and APs. - */ - use_cas : 1, - - __reserved : 61; -}; - -static struct sev_config sev_cfg __read_mostly; - static __always_inline bool on_vc_stack(struct pt_regs *regs) { unsigned long sp = regs->sp; @@ -2374,23 +2347,6 @@ static int __init report_snp_info(void) } arch_initcall(report_snp_info); -static int __init init_sev_config(char *str) -{ - char *s; - - while ((s = strsep(&str, ","))) { - if (!strcmp(s, "debug")) { - sev_cfg.debug = true; - continue; - } - - pr_info("SEV command-line option '%s' was not recognized\n", s); - } - - return 1; -} -__setup("sev=", init_sev_config); - static void update_attest_input(struct svsm_call *call, struct svsm_attest_call *input) { /* If (new) lengths have been returned, propagate them up */ diff --git a/arch/x86/include/asm/sev-common.h b/arch/x86/include/asm/sev-common.h index 98726c2b04f8..50f5666938c0 100644 --- a/arch/x86/include/asm/sev-common.h +++ b/arch/x86/include/asm/sev-common.h @@ -220,4 +220,31 @@ struct snp_psc_desc { #define GHCB_ERR_INVALID_INPUT 5 #define GHCB_ERR_INVALID_EVENT 6 +struct sev_config { + __u64 debug : 1, + + /* + * Indicates when the per-CPU GHCB has been created and registered + * and thus can be used by the BSP instead of the early boot GHCB. + * + * For APs, the per-CPU GHCB is created before they are started + * and registered upon startup, so this flag can be used globally + * for the BSP and APs. + */ + ghcbs_initialized : 1, + + /* + * Indicates when the per-CPU SVSM CA is to be used instead of the + * boot SVSM CA. + * + * For APs, the per-CPU SVSM CA is created as part of the AP + * bringup, so this flag can be used globally for the BSP and APs. + */ + use_cas : 1, + + __reserved : 61; +}; + +extern struct sev_config sev_cfg; + #endif diff --git a/arch/x86/virt/svm/Makefile b/arch/x86/virt/svm/Makefile index ef2a31bdcc70..eca6d71355fa 100644 --- a/arch/x86/virt/svm/Makefile +++ b/arch/x86/virt/svm/Makefile @@ -1,3 +1,4 @@ # SPDX-License-Identifier: GPL-2.0 obj-$(CONFIG_KVM_AMD_SEV) += sev.o +obj-$(CONFIG_CPU_SUP_AMD) += cmdline.o diff --git a/arch/x86/virt/svm/cmdline.c b/arch/x86/virt/svm/cmdline.c new file mode 100644 index 000000000000..9640507342e0 --- /dev/null +++ b/arch/x86/virt/svm/cmdline.c @@ -0,0 +1,32 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * AMD SVM-SEV command line parsing support + * + * Copyright (C) 2023 - 2024 Advanced Micro Devices, Inc. + * + * Author: Michael Roth <michael.roth@amd.com> + */ + +#include <linux/string.h> +#include <linux/printk.h> + +#include <asm/sev-common.h> + +struct sev_config sev_cfg __read_mostly; + +static int __init init_sev_config(char *str) +{ + char *s; + + while ((s = strsep(&str, ","))) { + if (!strcmp(s, "debug")) { + sev_cfg.debug = true; + continue; + } + + pr_info("SEV command-line option '%s' was not recognized\n", s); + } + + return 1; +} +__setup("sev=", init_sev_config); -- 2.34.1 ^ permalink raw reply related [flat|nested] 10+ messages in thread
* Re: [PATCH v6 1/2] x86, KVM:SVM: Move sev specific parsing into arch/x86/virt/svm 2024-10-10 12:14 ` [PATCH v6 1/2] x86, KVM:SVM: Move sev specific parsing into arch/x86/virt/svm Pavan Kumar Paluri @ 2024-10-11 16:21 ` Borislav Petkov 2024-10-11 16:35 ` Tom Lendacky 0 siblings, 1 reply; 10+ messages in thread From: Borislav Petkov @ 2024-10-11 16:21 UTC (permalink / raw) To: Pavan Kumar Paluri Cc: linux-kernel, linux-doc, linux-coco, Thomas Gleixner, Ingo Molnar, Dave Hansen, Eric Van Tassell, Tom Lendacky, Ashish Kalra, Michael Roth, H . Peter Anvin, Peter Zijlstra, Dhaval Giani On Thu, Oct 10, 2024 at 07:14:54AM -0500, Pavan Kumar Paluri wrote: > Move SEV specific kernel command line option parsing support from > arch/x86/coco/sev/core.c to arch/x86/virt/svm/cmdline.c so that both > host and guest related SEV command line options can be supported. > > No functional changes intended. > > Signed-off-by: Pavan Kumar Paluri <papaluri@amd.com> > Reviewed-by: Tom Lendacky <thomas.lendacky@amd.com> > --- > arch/x86/coco/sev/core.c | 44 ------------------------------- > arch/x86/include/asm/sev-common.h | 27 +++++++++++++++++++ > arch/x86/virt/svm/Makefile | 1 + > arch/x86/virt/svm/cmdline.c | 32 ++++++++++++++++++++++ > 4 files changed, 60 insertions(+), 44 deletions(-) > create mode 100644 arch/x86/virt/svm/cmdline.c make[5]: *** No rule to make target 'arch/x86/virt/svm/cmdline.o', needed by 'arch/x86/virt/svm/built-in.a'. Stop. make[5]: *** Waiting for unfinished jobs.... make[4]: *** [scripts/Makefile.build:478: arch/x86/virt/svm] Error 2 make[3]: *** [scripts/Makefile.build:478: arch/x86/virt] Error 2 make[3]: *** Waiting for unfinished jobs.... make[2]: *** [scripts/Makefile.build:478: arch/x86] Error 2 make[2]: *** Waiting for unfinished jobs.... make[1]: *** [/mnt/kernel/kernel/linux/Makefile:1936: .] Error 2 make: *** [Makefile:224: __sub-make] Error 2 $ ls arch/x86/virt/svm/cmdline.c ls: cannot access 'arch/x86/virt/svm/cmdline.c': No such file or directory Looks like you forgot to git add cmdline.c before committing. -- Regards/Gruss, Boris. https://people.kernel.org/tglx/notes-about-netiquette ^ permalink raw reply [flat|nested] 10+ messages in thread
* Re: [PATCH v6 1/2] x86, KVM:SVM: Move sev specific parsing into arch/x86/virt/svm 2024-10-11 16:21 ` Borislav Petkov @ 2024-10-11 16:35 ` Tom Lendacky 2024-10-11 16:48 ` Borislav Petkov 0 siblings, 1 reply; 10+ messages in thread From: Tom Lendacky @ 2024-10-11 16:35 UTC (permalink / raw) To: Borislav Petkov, Pavan Kumar Paluri Cc: linux-kernel, linux-doc, linux-coco, Thomas Gleixner, Ingo Molnar, Dave Hansen, Eric Van Tassell, Ashish Kalra, Michael Roth, H . Peter Anvin, Peter Zijlstra, Dhaval Giani On 10/11/24 11:21, Borislav Petkov wrote: > On Thu, Oct 10, 2024 at 07:14:54AM -0500, Pavan Kumar Paluri wrote: >> Move SEV specific kernel command line option parsing support from >> arch/x86/coco/sev/core.c to arch/x86/virt/svm/cmdline.c so that both >> host and guest related SEV command line options can be supported. >> >> No functional changes intended. >> >> Signed-off-by: Pavan Kumar Paluri <papaluri@amd.com> >> Reviewed-by: Tom Lendacky <thomas.lendacky@amd.com> >> --- >> arch/x86/coco/sev/core.c | 44 ------------------------------- >> arch/x86/include/asm/sev-common.h | 27 +++++++++++++++++++ >> arch/x86/virt/svm/Makefile | 1 + >> arch/x86/virt/svm/cmdline.c | 32 ++++++++++++++++++++++ >> 4 files changed, 60 insertions(+), 44 deletions(-) >> create mode 100644 arch/x86/virt/svm/cmdline.c > > make[5]: *** No rule to make target 'arch/x86/virt/svm/cmdline.o', needed by 'arch/x86/virt/svm/built-in.a'. Stop. > make[5]: *** Waiting for unfinished jobs.... > make[4]: *** [scripts/Makefile.build:478: arch/x86/virt/svm] Error 2 > make[3]: *** [scripts/Makefile.build:478: arch/x86/virt] Error 2 > make[3]: *** Waiting for unfinished jobs.... > make[2]: *** [scripts/Makefile.build:478: arch/x86] Error 2 > make[2]: *** Waiting for unfinished jobs.... > make[1]: *** [/mnt/kernel/kernel/linux/Makefile:1936: .] Error 2 > make: *** [Makefile:224: __sub-make] Error 2 > > $ ls arch/x86/virt/svm/cmdline.c > ls: cannot access 'arch/x86/virt/svm/cmdline.c': No such file or directory > > Looks like you forgot to git add cmdline.c before committing. But the patch includes the new file, so how can that be? Thanks, Tom > ^ permalink raw reply [flat|nested] 10+ messages in thread
* Re: [PATCH v6 1/2] x86, KVM:SVM: Move sev specific parsing into arch/x86/virt/svm 2024-10-11 16:35 ` Tom Lendacky @ 2024-10-11 16:48 ` Borislav Petkov 2024-10-11 16:55 ` Tom Lendacky 0 siblings, 1 reply; 10+ messages in thread From: Borislav Petkov @ 2024-10-11 16:48 UTC (permalink / raw) To: Tom Lendacky Cc: Pavan Kumar Paluri, linux-kernel, linux-doc, linux-coco, Thomas Gleixner, Ingo Molnar, Dave Hansen, Eric Van Tassell, Ashish Kalra, Michael Roth, H . Peter Anvin, Peter Zijlstra, Dhaval Giani On Fri, Oct 11, 2024 at 11:35:40AM -0500, Tom Lendacky wrote: > But the patch includes the new file, so how can that be? Ah, wrong error, sorry. This is his error: arch/x86/virt/svm/cmdline.c:15:27: error: expected ‘=’, ‘,’, ‘;’, ‘asm’ or ‘__attribute__’ before ‘__read_mostly’ 15 | struct sev_config sev_cfg __read_mostly; | ^~~~~~~~~~~~~ make[5]: *** [scripts/Makefile.build:229: arch/x86/virt/svm/cmdline.o] Error 1 make[4]: *** [scripts/Makefile.build:478: arch/x86/virt/svm] Error 2 make[3]: *** [scripts/Makefile.build:478: arch/x86/virt] Error 2 make[3]: *** Waiting for unfinished jobs.... make[2]: *** [scripts/Makefile.build:478: arch/x86] Error 2 make[2]: *** Waiting for unfinished jobs.... make[1]: *** [/mnt/kernel/kernel/2nd/linux/Makefile:1936: .] Error 2 make: *** [Makefile:224: __sub-make] Error 2 -- Regards/Gruss, Boris. https://people.kernel.org/tglx/notes-about-netiquette ^ permalink raw reply [flat|nested] 10+ messages in thread
* Re: [PATCH v6 1/2] x86, KVM:SVM: Move sev specific parsing into arch/x86/virt/svm 2024-10-11 16:48 ` Borislav Petkov @ 2024-10-11 16:55 ` Tom Lendacky 2024-10-11 16:59 ` Borislav Petkov 0 siblings, 1 reply; 10+ messages in thread From: Tom Lendacky @ 2024-10-11 16:55 UTC (permalink / raw) To: Borislav Petkov Cc: Pavan Kumar Paluri, linux-kernel, linux-doc, linux-coco, Thomas Gleixner, Ingo Molnar, Dave Hansen, Eric Van Tassell, Ashish Kalra, Michael Roth, H . Peter Anvin, Peter Zijlstra, Dhaval Giani On 10/11/24 11:48, Borislav Petkov wrote: > On Fri, Oct 11, 2024 at 11:35:40AM -0500, Tom Lendacky wrote: >> But the patch includes the new file, so how can that be? > > Ah, wrong error, sorry. > > This is his error: > > arch/x86/virt/svm/cmdline.c:15:27: error: expected ‘=’, ‘,’, ‘;’, ‘asm’ or ‘__attribute__’ before ‘__read_mostly’ > 15 | struct sev_config sev_cfg __read_mostly; > | ^~~~~~~~~~~~~ > make[5]: *** [scripts/Makefile.build:229: arch/x86/virt/svm/cmdline.o] Error 1 > make[4]: *** [scripts/Makefile.build:478: arch/x86/virt/svm] Error 2 > make[3]: *** [scripts/Makefile.build:478: arch/x86/virt] Error 2 > make[3]: *** Waiting for unfinished jobs.... > make[2]: *** [scripts/Makefile.build:478: arch/x86] Error 2 > make[2]: *** Waiting for unfinished jobs.... > make[1]: *** [/mnt/kernel/kernel/2nd/linux/Makefile:1936: .] Error 2 > make: *** [Makefile:224: __sub-make] Error 2 Ah, that makes more sense. Looks like he's missing the include for linux/cache.h Thanks, Tom > ^ permalink raw reply [flat|nested] 10+ messages in thread
* Re: [PATCH v6 1/2] x86, KVM:SVM: Move sev specific parsing into arch/x86/virt/svm 2024-10-11 16:55 ` Tom Lendacky @ 2024-10-11 16:59 ` Borislav Petkov 2024-10-11 17:08 ` Paluri, PavanKumar 0 siblings, 1 reply; 10+ messages in thread From: Borislav Petkov @ 2024-10-11 16:59 UTC (permalink / raw) To: Tom Lendacky Cc: Pavan Kumar Paluri, linux-kernel, linux-doc, linux-coco, Thomas Gleixner, Ingo Molnar, Dave Hansen, Eric Van Tassell, Ashish Kalra, Michael Roth, H . Peter Anvin, Peter Zijlstra, Dhaval Giani On Fri, Oct 11, 2024 at 11:55:14AM -0500, Tom Lendacky wrote: > Ah, that makes more sense. Looks like he's missing the include for > linux/cache.h "Changelog: ========= v5: ... * Remove <asm/cache.h> stray header introduced in the previous versions because of __read_mostly attribute that is now moved into virt/svm/cmdline.c" -- Regards/Gruss, Boris. https://people.kernel.org/tglx/notes-about-netiquette ^ permalink raw reply [flat|nested] 10+ messages in thread
* Re: [PATCH v6 1/2] x86, KVM:SVM: Move sev specific parsing into arch/x86/virt/svm 2024-10-11 16:59 ` Borislav Petkov @ 2024-10-11 17:08 ` Paluri, PavanKumar 2024-10-11 22:16 ` Borislav Petkov 0 siblings, 1 reply; 10+ messages in thread From: Paluri, PavanKumar @ 2024-10-11 17:08 UTC (permalink / raw) To: Borislav Petkov, Tom Lendacky Cc: linux-kernel, linux-doc, linux-coco, Thomas Gleixner, Ingo Molnar, Dave Hansen, Eric Van Tassell, Ashish Kalra, Michael Roth, H . Peter Anvin, Peter Zijlstra, Dhaval Giani Hello Boris, On 10/11/2024 11:59 AM, Borislav Petkov wrote: > On Fri, Oct 11, 2024 at 11:55:14AM -0500, Tom Lendacky wrote: >> Ah, that makes more sense. Looks like he's missing the include for >> linux/cache.h > > "Changelog: > ========= > v5: > ... > * Remove <asm/cache.h> stray header introduced in the previous > versions because of __read_mostly attribute that is now moved into > virt/svm/cmdline.c" > Yes, I am very sorry. I should have done a progressive build, which could have helped me in spotting this issue. This changelog points at removing <asm/cache.h> from arch/x86/include/asm/sev-common.h (where __read_mostly was previously present) and forgot to include this header to where it is now relocated to. I will address this. On building the patchset (1 and 2 together), I do not see the error, so this should have occurred on just building Patch #1. Thanks for the review. Pavan ^ permalink raw reply [flat|nested] 10+ messages in thread
* Re: [PATCH v6 1/2] x86, KVM:SVM: Move sev specific parsing into arch/x86/virt/svm 2024-10-11 17:08 ` Paluri, PavanKumar @ 2024-10-11 22:16 ` Borislav Petkov 0 siblings, 0 replies; 10+ messages in thread From: Borislav Petkov @ 2024-10-11 22:16 UTC (permalink / raw) To: Paluri, PavanKumar Cc: Tom Lendacky, linux-kernel, linux-doc, linux-coco, Thomas Gleixner, Ingo Molnar, Dave Hansen, Eric Van Tassell, Ashish Kalra, Michael Roth, H . Peter Anvin, Peter Zijlstra, Dhaval Giani On Fri, Oct 11, 2024 at 12:08:34PM -0500, Paluri, PavanKumar wrote: > On building the patchset (1 and 2 together), I do not see the error, so this > should have occurred on just building Patch #1. You always, *always* must build-test each patch. Imagine someone is bisecting the kernel and bisection lands at your patch which doesn't even build... We can't have that. -- Regards/Gruss, Boris. https://people.kernel.org/tglx/notes-about-netiquette ^ permalink raw reply [flat|nested] 10+ messages in thread
* [PATCH v6 2/2] x86 KVM:SVM: Provide "nosnp" boot option for sev kernel command line 2024-10-10 12:14 [PATCH v6 0/2] nosnp sev command line support Pavan Kumar Paluri 2024-10-10 12:14 ` [PATCH v6 1/2] x86, KVM:SVM: Move sev specific parsing into arch/x86/virt/svm Pavan Kumar Paluri @ 2024-10-10 12:14 ` Pavan Kumar Paluri 1 sibling, 0 replies; 10+ messages in thread From: Pavan Kumar Paluri @ 2024-10-10 12:14 UTC (permalink / raw) To: linux-kernel Cc: linux-doc, linux-coco, Borislav Petkov, Thomas Gleixner, Ingo Molnar, Dave Hansen, Eric Van Tassell, Tom Lendacky, Ashish Kalra, Michael Roth, H . Peter Anvin, Peter Zijlstra, Pavan Kumar Paluri, Dhaval Giani Provide a "nosnp" kernel command line option to prevent enabling of the RMP and SEV-SNP features in the host/hypervisor. Not initializing the RMP removes system overhead associated with RMP checks. Co-developed-by: Eric Van Tassell <Eric.VanTassell@amd.com> Signed-off-by: Eric Van Tassell <Eric.VanTassell@amd.com> Signed-off-by: Pavan Kumar Paluri <papaluri@amd.com> Reviewed-by: Tom Lendacky <thomas.lendacky@amd.com> --- Documentation/arch/x86/x86_64/boot-options.rst | 5 +++++ arch/x86/virt/svm/cmdline.c | 7 +++++++ 2 files changed, 12 insertions(+) diff --git a/Documentation/arch/x86/x86_64/boot-options.rst b/Documentation/arch/x86/x86_64/boot-options.rst index 98d4805f0823..d69e3cfbdba5 100644 --- a/Documentation/arch/x86/x86_64/boot-options.rst +++ b/Documentation/arch/x86/x86_64/boot-options.rst @@ -305,3 +305,8 @@ The available options are: debug Enable debug messages. + + nosnp + Do not enable SEV-SNP (applies to host/hypervisor only). Setting + 'nosnp' avoids the RMP check overhead in memory accesses when + users do not want to run SEV-SNP guests. diff --git a/arch/x86/virt/svm/cmdline.c b/arch/x86/virt/svm/cmdline.c index 9640507342e0..313415d6f53f 100644 --- a/arch/x86/virt/svm/cmdline.c +++ b/arch/x86/virt/svm/cmdline.c @@ -11,6 +11,7 @@ #include <linux/printk.h> #include <asm/sev-common.h> +#include <asm/cpufeature.h> struct sev_config sev_cfg __read_mostly; @@ -24,6 +25,12 @@ static int __init init_sev_config(char *str) continue; } + if (!strcmp(s, "nosnp")) { + setup_clear_cpu_cap(X86_FEATURE_SEV_SNP); + cc_platform_clear(CC_ATTR_HOST_SEV_SNP); + continue; + } + pr_info("SEV command-line option '%s' was not recognized\n", s); } -- 2.34.1 ^ permalink raw reply related [flat|nested] 10+ messages in thread
end of thread, other threads:[~2024-10-11 22:16 UTC | newest] Thread overview: 10+ messages (download: mbox.gz follow: Atom feed -- links below jump to the message on this page -- 2024-10-10 12:14 [PATCH v6 0/2] nosnp sev command line support Pavan Kumar Paluri 2024-10-10 12:14 ` [PATCH v6 1/2] x86, KVM:SVM: Move sev specific parsing into arch/x86/virt/svm Pavan Kumar Paluri 2024-10-11 16:21 ` Borislav Petkov 2024-10-11 16:35 ` Tom Lendacky 2024-10-11 16:48 ` Borislav Petkov 2024-10-11 16:55 ` Tom Lendacky 2024-10-11 16:59 ` Borislav Petkov 2024-10-11 17:08 ` Paluri, PavanKumar 2024-10-11 22:16 ` Borislav Petkov 2024-10-10 12:14 ` [PATCH v6 2/2] x86 KVM:SVM: Provide "nosnp" boot option for sev kernel command line Pavan Kumar Paluri
This is a public inbox, see mirroring instructions for how to clone and mirror all data and code used for this inbox