| Message ID | 20210820155918.7518-5-brijesh.singh@amd.com (mailing list archive) |
|---|---|
| State | Not Applicable |
| Delegated to: | Herbert Xu |
| Headers | show |
| Series | Add AMD Secure Nested Paging (SEV-SNP) Hypervisor Support | expand |
On Fri, Aug 20, 2021 at 10:58:37AM -0500, Brijesh Singh wrote: > +struct __packed rmpentry { > + union { > + struct { > + u64 assigned : 1, > + pagesize : 1, > + immutable : 1, > + rsvd1 : 9, > + gpa : 39, > + asid : 10, > + vmsa : 1, > + validated : 1, > + rsvd2 : 1; > + } info; > + u64 low; > + }; > + u64 high; > +}; __packed goes at the end of the struct definition. > + > +#define rmpentry_assigned(x) ((x)->info.assigned) > +#define rmpentry_pagesize(x) ((x)->info.pagesize) Inline functions pls so that you can get typechecking too. > > #define RMPADJUST_VMSA_PAGE_BIT BIT(16) > > diff --git a/arch/x86/kernel/sev.c b/arch/x86/kernel/sev.c > index 7936c8139c74..f383d2a89263 100644 > --- a/arch/x86/kernel/sev.c > +++ b/arch/x86/kernel/sev.c > @@ -54,6 +54,8 @@ > * bookkeeping, the range need to be added during the RMP entry lookup. > */ > #define RMPTABLE_CPU_BOOKKEEPING_SZ 0x4000 > +#define RMPENTRY_SHIFT 8 > +#define rmptable_page_offset(x) (RMPTABLE_CPU_BOOKKEEPING_SZ + (((unsigned long)x) >> RMPENTRY_SHIFT)) > > /* For early boot hypervisor communication in SEV-ES enabled guests */ > static struct ghcb boot_ghcb_page __bss_decrypted __aligned(PAGE_SIZE); > @@ -2376,3 +2378,44 @@ static int __init snp_rmptable_init(void) > * available after subsys_initcall(). > */ > fs_initcall(snp_rmptable_init); > + > +static struct rmpentry *__snp_lookup_rmpentry(u64 pfn, int *level) > +{ > + unsigned long vaddr, paddr = pfn << PAGE_SHIFT; > + struct rmpentry *entry, *large_entry; > + > + if (!pfn_valid(pfn)) > + return ERR_PTR(-EINVAL); > + > + if (!cpu_feature_enabled(X86_FEATURE_SEV_SNP)) > + return ERR_PTR(-ENXIO); I think that check should happen first. > + > + vaddr = rmptable_start + rmptable_page_offset(paddr); > + if (unlikely(vaddr > rmptable_end)) > + return ERR_PTR(-ENXIO); Maybe the above -E should be -ENOENT instead so that you have unique error types for each check to facilitate debugging. > + > + entry = (struct rmpentry *)vaddr; > + > + /* Read a large RMP entry to get the correct page level used in RMP entry. */ That comment needs rewriting. > + vaddr = rmptable_start + rmptable_page_offset(paddr & PMD_MASK); > + large_entry = (struct rmpentry *)vaddr; > + *level = RMP_TO_X86_PG_LEVEL(rmpentry_pagesize(large_entry)); > + > + return entry; > +} > + > +/* > + * Return 1 if the RMP entry is assigned, 0 if it exists but is not assigned, > + * and -errno if there is no corresponding RMP entry. > + */ kernel-doc format since it is being exported. > +int snp_lookup_rmpentry(u64 pfn, int *level) > +{ > + struct rmpentry *e; > + > + e = __snp_lookup_rmpentry(pfn, level); > + if (IS_ERR(e)) > + return PTR_ERR(e); > + > + return !!rmpentry_assigned(e); > +} > +EXPORT_SYMBOL_GPL(snp_lookup_rmpentry); This export is for kvm, I presume? > diff --git a/include/linux/sev.h b/include/linux/sev.h > new file mode 100644 > index 000000000000..1a68842789e1 > --- /dev/null > +++ b/include/linux/sev.h > @@ -0,0 +1,30 @@ > +/* SPDX-License-Identifier: GPL-2.0 */ > +/* > + * AMD Secure Encrypted Virtualization > + * > + * Author: Brijesh Singh <brijesh.singh@amd.com> > + */ > + > +#ifndef __LINUX_SEV_H > +#define __LINUX_SEV_H > + > +/* RMUPDATE detected 4K page and 2MB page overlap. */ > +#define RMPUPDATE_FAIL_OVERLAP 7 > + > +#ifdef CONFIG_AMD_MEM_ENCRYPT > +int snp_lookup_rmpentry(u64 pfn, int *level); > +int psmash(u64 pfn); > +int rmp_make_private(u64 pfn, u64 gpa, enum pg_level level, int asid, bool immutable); > +int rmp_make_shared(u64 pfn, enum pg_level level); > +#else > +static inline int snp_lookup_rmpentry(u64 pfn, int *level) { return 0; } > +static inline int psmash(u64 pfn) { return -ENXIO; } > +static inline int rmp_make_private(u64 pfn, u64 gpa, enum pg_level level, int asid, > + bool immutable) > +{ > + return -ENODEV; > +} > +static inline int rmp_make_shared(u64 pfn, enum pg_level level) { return -ENODEV; } > + > +#endif /* CONFIG_AMD_MEM_ENCRYPT */ > +#endif /* __LINUX_SEV_H */ > -- What is going to use this linux/ namespace header?
Hi Boris, I agreed with all of your comment, responding to your specific questions. On 9/24/21 4:49 AM, Borislav Petkov wrote: ... >> +} >> +EXPORT_SYMBOL_GPL(snp_lookup_rmpentry); > > This export is for kvm, I presume? yes, both KVM and CCP (i.e PSP) driver will need to lookup RMP entries. > >> diff --git a/include/linux/sev.h b/include/linux/sev.h >> new file mode 100644 >> index 000000000000..1a68842789e1 >> --- /dev/null >> +++ b/include/linux/sev.h >> @@ -0,0 +1,30 @@ >> +/* SPDX-License-Identifier: GPL-2.0 */ >> +/* >> + * AMD Secure Encrypted Virtualization >> + * >> + * Author: Brijesh Singh <brijesh.singh@amd.com> >> + */ >> + >> +#ifndef __LINUX_SEV_H >> +#define __LINUX_SEV_H >> + >> +/* RMUPDATE detected 4K page and 2MB page overlap. */ >> +#define RMPUPDATE_FAIL_OVERLAP 7 >> + >> +#ifdef CONFIG_AMD_MEM_ENCRYPT >> +int snp_lookup_rmpentry(u64 pfn, int *level); >> +int psmash(u64 pfn); >> +int rmp_make_private(u64 pfn, u64 gpa, enum pg_level level, int asid, bool immutable); >> +int rmp_make_shared(u64 pfn, enum pg_level level); >> +#else >> +static inline int snp_lookup_rmpentry(u64 pfn, int *level) { return 0; } >> +static inline int psmash(u64 pfn) { return -ENXIO; } >> +static inline int rmp_make_private(u64 pfn, u64 gpa, enum pg_level level, int asid, >> + bool immutable) >> +{ >> + return -ENODEV; >> +} >> +static inline int rmp_make_shared(u64 pfn, enum pg_level level) { return -ENODEV; } >> + >> +#endif /* CONFIG_AMD_MEM_ENCRYPT */ >> +#endif /* __LINUX_SEV_H */ >> -- > > What is going to use this linux/ namespace header? > The kvm and ccp drivers.
On 9/27/21 11:01 AM, Brijesh Singh wrote: >>> -- >> >> What is going to use this linux/ namespace header? >> > > The kvm and ccp drivers. Currently, we have only x86 drivers using it, are you thinking to move this to arch/x86/include/asm/ ? thanks
On Mon, Sep 27, 2021 at 11:04:04AM -0500, Brijesh Singh wrote: > Currently, we have only x86 drivers using it, are you thinking to move > this to arch/x86/include/asm/ ? arch/x86/include/asm/sev.h, yap. We can always create it later if needed by other architectures. Thx.
On Fri, Aug 20, 2021 at 10:58:37AM -0500, Brijesh Singh wrote: > The snp_lookup_page_in_rmptable() can be used by the host to read the RMP > entry for a given page. The RMP entry format is documented in AMD PPR, see > https://bugzilla.kernel.org/attachment.cgi?id=296015. > > Signed-off-by: Brijesh Singh <brijesh.singh@amd.com> > --- > arch/x86/include/asm/sev.h | 27 ++++++++++++++++++++++++ > arch/x86/kernel/sev.c | 43 ++++++++++++++++++++++++++++++++++++++ > include/linux/sev.h | 30 ++++++++++++++++++++++++++ > 3 files changed, 100 insertions(+) > create mode 100644 include/linux/sev.h > > diff --git a/arch/x86/include/asm/sev.h b/arch/x86/include/asm/sev.h > index a5f0a1c3ccbe..5b1a6a075c47 100644 > --- a/arch/x86/include/asm/sev.h > +++ b/arch/x86/include/asm/sev.h > @@ -9,6 +9,7 @@ > #define __ASM_ENCRYPTED_STATE_H > > #include <linux/types.h> > +#include <linux/sev.h> > #include <asm/insn.h> > #include <asm/sev-common.h> > #include <asm/bootparam.h> > @@ -77,6 +78,32 @@ extern bool handle_vc_boot_ghcb(struct pt_regs *regs); > > /* RMP page size */ > #define RMP_PG_SIZE_4K 0 > +#define RMP_TO_X86_PG_LEVEL(level) (((level) == RMP_PG_SIZE_4K) ? PG_LEVEL_4K : PG_LEVEL_2M) > + > +/* > + * The RMP entry format is not architectural. The format is defined in PPR > + * Family 19h Model 01h, Rev B1 processor. > + */ > +struct __packed rmpentry { > + union { > + struct { > + u64 assigned : 1, > + pagesize : 1, > + immutable : 1, > + rsvd1 : 9, > + gpa : 39, > + asid : 10, > + vmsa : 1, > + validated : 1, > + rsvd2 : 1; > + } info; > + u64 low; > + }; > + u64 high; > +}; > + > +#define rmpentry_assigned(x) ((x)->info.assigned) > +#define rmpentry_pagesize(x) ((x)->info.pagesize) > > #define RMPADJUST_VMSA_PAGE_BIT BIT(16) > > diff --git a/arch/x86/kernel/sev.c b/arch/x86/kernel/sev.c > index 7936c8139c74..f383d2a89263 100644 > --- a/arch/x86/kernel/sev.c > +++ b/arch/x86/kernel/sev.c > @@ -54,6 +54,8 @@ > * bookkeeping, the range need to be added during the RMP entry lookup. > */ > #define RMPTABLE_CPU_BOOKKEEPING_SZ 0x4000 > +#define RMPENTRY_SHIFT 8 > +#define rmptable_page_offset(x) (RMPTABLE_CPU_BOOKKEEPING_SZ + (((unsigned long)x) >> RMPENTRY_SHIFT)) > > /* For early boot hypervisor communication in SEV-ES enabled guests */ > static struct ghcb boot_ghcb_page __bss_decrypted __aligned(PAGE_SIZE); > @@ -2376,3 +2378,44 @@ static int __init snp_rmptable_init(void) > * available after subsys_initcall(). > */ > fs_initcall(snp_rmptable_init); > + > +static struct rmpentry *__snp_lookup_rmpentry(u64 pfn, int *level) > +{ > + unsigned long vaddr, paddr = pfn << PAGE_SHIFT; > + struct rmpentry *entry, *large_entry; > + > + if (!pfn_valid(pfn)) > + return ERR_PTR(-EINVAL); > + > + if (!cpu_feature_enabled(X86_FEATURE_SEV_SNP)) > + return ERR_PTR(-ENXIO); > + > + vaddr = rmptable_start + rmptable_page_offset(paddr); > + if (unlikely(vaddr > rmptable_end)) > + return ERR_PTR(-ENXIO); > + > + entry = (struct rmpentry *)vaddr; > + > + /* Read a large RMP entry to get the correct page level used in RMP entry. */ > + vaddr = rmptable_start + rmptable_page_offset(paddr & PMD_MASK); > + large_entry = (struct rmpentry *)vaddr; > + *level = RMP_TO_X86_PG_LEVEL(rmpentry_pagesize(large_entry)); > + > + return entry; > +} > + > +/* > + * Return 1 if the RMP entry is assigned, 0 if it exists but is not assigned, > + * and -errno if there is no corresponding RMP entry. According to /usr/include/asm-generic/errno.h, there is 133 error codes. Why you need so many just to say that there is no entry? > + */ > +int snp_lookup_rmpentry(u64 pfn, int *level) > +{ > + struct rmpentry *e; > + > + e = __snp_lookup_rmpentry(pfn, level); > + if (IS_ERR(e)) > + return PTR_ERR(e); > + > + return !!rmpentry_assigned(e); > +} > +EXPORT_SYMBOL_GPL(snp_lookup_rmpentry); > diff --git a/include/linux/sev.h b/include/linux/sev.h > new file mode 100644 > index 000000000000..1a68842789e1 > --- /dev/null > +++ b/include/linux/sev.h > @@ -0,0 +1,30 @@ > +/* SPDX-License-Identifier: GPL-2.0 */ > +/* > + * AMD Secure Encrypted Virtualization > + * > + * Author: Brijesh Singh <brijesh.singh@amd.com> nit: this is redundant. Each git commit has an author-field. > + */ > + > +#ifndef __LINUX_SEV_H > +#define __LINUX_SEV_H > + > +/* RMUPDATE detected 4K page and 2MB page overlap. */ > +#define RMPUPDATE_FAIL_OVERLAP 7 > + > +#ifdef CONFIG_AMD_MEM_ENCRYPT > +int snp_lookup_rmpentry(u64 pfn, int *level); > +int psmash(u64 pfn); > +int rmp_make_private(u64 pfn, u64 gpa, enum pg_level level, int asid, bool immutable); > +int rmp_make_shared(u64 pfn, enum pg_level level); > +#else > +static inline int snp_lookup_rmpentry(u64 pfn, int *level) { return 0; } > +static inline int psmash(u64 pfn) { return -ENXIO; } > +static inline int rmp_make_private(u64 pfn, u64 gpa, enum pg_level level, int asid, > + bool immutable) > +{ > + return -ENODEV; > +} > +static inline int rmp_make_shared(u64 pfn, enum pg_level level) { return -ENODEV; } > + > +#endif /* CONFIG_AMD_MEM_ENCRYPT */ > +#endif /* __LINUX_SEV_H */ > -- > 2.17.1 > BR, Jarkko
diff --git a/arch/x86/include/asm/sev.h b/arch/x86/include/asm/sev.h index a5f0a1c3ccbe..5b1a6a075c47 100644 --- a/arch/x86/include/asm/sev.h +++ b/arch/x86/include/asm/sev.h @@ -9,6 +9,7 @@ #define __ASM_ENCRYPTED_STATE_H #include <linux/types.h> +#include <linux/sev.h> #include <asm/insn.h> #include <asm/sev-common.h> #include <asm/bootparam.h> @@ -77,6 +78,32 @@ extern bool handle_vc_boot_ghcb(struct pt_regs *regs); /* RMP page size */ #define RMP_PG_SIZE_4K 0 +#define RMP_TO_X86_PG_LEVEL(level) (((level) == RMP_PG_SIZE_4K) ? PG_LEVEL_4K : PG_LEVEL_2M) + +/* + * The RMP entry format is not architectural. The format is defined in PPR + * Family 19h Model 01h, Rev B1 processor. + */ +struct __packed rmpentry { + union { + struct { + u64 assigned : 1, + pagesize : 1, + immutable : 1, + rsvd1 : 9, + gpa : 39, + asid : 10, + vmsa : 1, + validated : 1, + rsvd2 : 1; + } info; + u64 low; + }; + u64 high; +}; + +#define rmpentry_assigned(x) ((x)->info.assigned) +#define rmpentry_pagesize(x) ((x)->info.pagesize) #define RMPADJUST_VMSA_PAGE_BIT BIT(16) diff --git a/arch/x86/kernel/sev.c b/arch/x86/kernel/sev.c index 7936c8139c74..f383d2a89263 100644 --- a/arch/x86/kernel/sev.c +++ b/arch/x86/kernel/sev.c @@ -54,6 +54,8 @@ * bookkeeping, the range need to be added during the RMP entry lookup. */ #define RMPTABLE_CPU_BOOKKEEPING_SZ 0x4000 +#define RMPENTRY_SHIFT 8 +#define rmptable_page_offset(x) (RMPTABLE_CPU_BOOKKEEPING_SZ + (((unsigned long)x) >> RMPENTRY_SHIFT)) /* For early boot hypervisor communication in SEV-ES enabled guests */ static struct ghcb boot_ghcb_page __bss_decrypted __aligned(PAGE_SIZE); @@ -2376,3 +2378,44 @@ static int __init snp_rmptable_init(void) * available after subsys_initcall(). */ fs_initcall(snp_rmptable_init); + +static struct rmpentry *__snp_lookup_rmpentry(u64 pfn, int *level) +{ + unsigned long vaddr, paddr = pfn << PAGE_SHIFT; + struct rmpentry *entry, *large_entry; + + if (!pfn_valid(pfn)) + return ERR_PTR(-EINVAL); + + if (!cpu_feature_enabled(X86_FEATURE_SEV_SNP)) + return ERR_PTR(-ENXIO); + + vaddr = rmptable_start + rmptable_page_offset(paddr); + if (unlikely(vaddr > rmptable_end)) + return ERR_PTR(-ENXIO); + + entry = (struct rmpentry *)vaddr; + + /* Read a large RMP entry to get the correct page level used in RMP entry. */ + vaddr = rmptable_start + rmptable_page_offset(paddr & PMD_MASK); + large_entry = (struct rmpentry *)vaddr; + *level = RMP_TO_X86_PG_LEVEL(rmpentry_pagesize(large_entry)); + + return entry; +} + +/* + * Return 1 if the RMP entry is assigned, 0 if it exists but is not assigned, + * and -errno if there is no corresponding RMP entry. + */ +int snp_lookup_rmpentry(u64 pfn, int *level) +{ + struct rmpentry *e; + + e = __snp_lookup_rmpentry(pfn, level); + if (IS_ERR(e)) + return PTR_ERR(e); + + return !!rmpentry_assigned(e); +} +EXPORT_SYMBOL_GPL(snp_lookup_rmpentry); diff --git a/include/linux/sev.h b/include/linux/sev.h new file mode 100644 index 000000000000..1a68842789e1 --- /dev/null +++ b/include/linux/sev.h @@ -0,0 +1,30 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * AMD Secure Encrypted Virtualization + * + * Author: Brijesh Singh <brijesh.singh@amd.com> + */ + +#ifndef __LINUX_SEV_H +#define __LINUX_SEV_H + +/* RMUPDATE detected 4K page and 2MB page overlap. */ +#define RMPUPDATE_FAIL_OVERLAP 7 + +#ifdef CONFIG_AMD_MEM_ENCRYPT +int snp_lookup_rmpentry(u64 pfn, int *level); +int psmash(u64 pfn); +int rmp_make_private(u64 pfn, u64 gpa, enum pg_level level, int asid, bool immutable); +int rmp_make_shared(u64 pfn, enum pg_level level); +#else +static inline int snp_lookup_rmpentry(u64 pfn, int *level) { return 0; } +static inline int psmash(u64 pfn) { return -ENXIO; } +static inline int rmp_make_private(u64 pfn, u64 gpa, enum pg_level level, int asid, + bool immutable) +{ + return -ENODEV; +} +static inline int rmp_make_shared(u64 pfn, enum pg_level level) { return -ENODEV; } + +#endif /* CONFIG_AMD_MEM_ENCRYPT */ +#endif /* __LINUX_SEV_H */
The snp_lookup_page_in_rmptable() can be used by the host to read the RMP entry for a given page. The RMP entry format is documented in AMD PPR, see https://bugzilla.kernel.org/attachment.cgi?id=296015. Signed-off-by: Brijesh Singh <brijesh.singh@amd.com> --- arch/x86/include/asm/sev.h | 27 ++++++++++++++++++++++++ arch/x86/kernel/sev.c | 43 ++++++++++++++++++++++++++++++++++++++ include/linux/sev.h | 30 ++++++++++++++++++++++++++ 3 files changed, 100 insertions(+) create mode 100644 include/linux/sev.h