On Mon, Oct 16, 2023 at 08:27:36AM -0500, Michael Roth wrote: > From: Brijesh Singh <brijesh.singh@xxxxxxx> > > The snp_lookup_page_in_rmptable() can be used by the host to read the RMP $ git grep snp_lookup_page_in_rmptable $ Stale commit message. And not very telling. Please rewrite. > entry for a given page. The RMP entry format is documented in AMD PPR, see > https://bugzilla.kernel.org/attachment.cgi?id=296015. <--- Brijesh's SOB comes first here if he's the primary author. > Co-developed-by: Ashish Kalra <ashish.kalra@xxxxxxx> > Signed-off-by: Ashish Kalra <ashish.kalra@xxxxxxx> > Signed-off-by: Brijesh Singh <brijesh.singh@xxxxxxx> > [mdr: separate 'assigned' indicator from return code] > Signed-off-by: Michael Roth <michael.roth@xxxxxxx> > --- > arch/x86/include/asm/sev-common.h | 4 +++ > arch/x86/include/asm/sev-host.h | 22 +++++++++++++ > arch/x86/virt/svm/sev.c | 53 +++++++++++++++++++++++++++++++ > 3 files changed, 79 insertions(+) > create mode 100644 arch/x86/include/asm/sev-host.h > > diff --git a/arch/x86/include/asm/sev-common.h b/arch/x86/include/asm/sev-common.h > index b463fcbd4b90..1e6fb93d8ab0 100644 > --- a/arch/x86/include/asm/sev-common.h > +++ b/arch/x86/include/asm/sev-common.h > @@ -173,4 +173,8 @@ struct snp_psc_desc { > #define GHCB_ERR_INVALID_INPUT 5 > #define GHCB_ERR_INVALID_EVENT 6 > > +/* RMP page size */ > +#define RMP_PG_SIZE_4K 0 RMP_PG_LEVEL_4K just like the generic ones. > +#define RMP_TO_X86_PG_LEVEL(level) (((level) == RMP_PG_SIZE_4K) ? PG_LEVEL_4K : PG_LEVEL_2M) What else is there besides X86 PG level? IOW, RMP_TO_PG_LEVEL simply. > + > #endif > diff --git a/arch/x86/include/asm/sev-host.h b/arch/x86/include/asm/sev-host.h Nah, we don't need a third sev header: arch/x86/include/asm/sev-common.h arch/x86/include/asm/sev.h arch/x86/include/asm/sev-host.h Put it in sev.h pls. sev-common.h should be merged into sev.h too unless there's a compelling reason not to which I don't see atm. > new file mode 100644 > index 000000000000..4c487ce8457f > --- /dev/null > +++ b/arch/x86/include/asm/sev-host.h ... > diff --git a/arch/x86/virt/svm/sev.c b/arch/x86/virt/svm/sev.c > index 8b9ed72489e4..7d3802605376 100644 > --- a/arch/x86/virt/svm/sev.c > +++ b/arch/x86/virt/svm/sev.c > @@ -53,6 +53,9 @@ struct rmpentry { > */ > #define RMPTABLE_CPU_BOOKKEEPING_SZ 0x4000 > > +/* Mask to apply to a PFN to get the first PFN of a 2MB page */ > +#define PFN_PMD_MASK (~((1ULL << (PMD_SHIFT - PAGE_SHIFT)) - 1)) GENMASK_ULL > static struct rmpentry *rmptable_start __ro_after_init; > static u64 rmptable_max_pfn __ro_after_init; > > @@ -237,3 +240,53 @@ static int __init snp_rmptable_init(void) > * the page(s) used for DMA are hypervisor owned. > */ > fs_initcall(snp_rmptable_init); > + > +static int rmptable_entry(u64 pfn, struct rmpentry *entry) The signature of this one should be: static struct rmpentry *get_rmp_entry(u64 pfn) and the callers should use the IS_ERR* macros to check whether it returns a valid pointer or a negative value for error. Ditto for the other two functions here. > + if (WARN_ON_ONCE(pfn > rmptable_max_pfn)) > + return -EFAULT; > + > + *entry = rmptable_start[pfn]; This wants to be called rmptable[] then. > + > + return 0; > +} > + > +static int __snp_lookup_rmpentry(u64 pfn, struct rmpentry *entry, int *level) > +{ > + struct rmpentry large_entry; > + int ret; > + > + if (!cpu_feature_enabled(X86_FEATURE_SEV_SNP)) > + return -ENXIO; ENODEV or so. > + > + ret = rmptable_entry(pfn, entry); > + if (ret) > + return ret; > + > + /* > + * Find the authoritative RMP entry for a PFN. This can be either a 4K > + * RMP entry or a special large RMP entry that is authoritative for a > + * whole 2M area. > + */ > + ret = rmptable_entry(pfn & PFN_PMD_MASK, &large_entry); > + if (ret) > + return ret; > + > + *level = RMP_TO_X86_PG_LEVEL(large_entry.pagesize); > + > + return 0; > +} > + > +int snp_lookup_rmpentry(u64 pfn, bool *assigned, int *level) > +{ > + struct rmpentry e; > + int ret; > + > + ret = __snp_lookup_rmpentry(pfn, &e, level); > + if (ret) > + return ret; > + > + *assigned = !!e.assigned; > + return 0; > +} > +EXPORT_SYMBOL_GPL(snp_lookup_rmpentry); > -- Thx. -- Regards/Gruss, Boris. https://people.kernel.org/tglx/notes-about-netiquette
