The kernel provides infrastructure to set or clear the encryption mask from the pages for AMD SEV, but TDX requires few tweaks. - TDX and SEV have different requirements to the cache and TLB flushing. - TDX has own routine to notify VMM about page encryption status change. Modify __set_memory_enc_pgtable() and make it flexible enough to cover both AMD SEV and Intel TDX. The AMD-specific behavior is isolated in callback under x86_platform_cc. TDX will provide own version of the callbacks. [ bp: Beat into submission. ] Signed-off-by: Brijesh Singh <brijesh.singh@xxxxxxx> Signed-off-by: Borislav Petkov <bp@xxxxxxx> Link: https://lore.kernel.org/r/20220223043528.2093214-1-brijesh.singh@xxxxxxx --- arch/x86/include/asm/set_memory.h | 1 - arch/x86/include/asm/x86_init.h | 16 +++++++ arch/x86/kernel/x86_init.c | 16 ++++++- arch/x86/mm/mem_encrypt_amd.c | 71 +++++++++++++++++++++---------- arch/x86/mm/pat/set_memory.c | 18 ++++---- 5 files changed, 88 insertions(+), 34 deletions(-) diff --git a/arch/x86/include/asm/set_memory.h b/arch/x86/include/asm/set_memory.h index ff0f2d90338a..ce8dd215f5b3 100644 --- a/arch/x86/include/asm/set_memory.h +++ b/arch/x86/include/asm/set_memory.h @@ -84,7 +84,6 @@ int set_pages_rw(struct page *page, int numpages); int set_direct_map_invalid_noflush(struct page *page); int set_direct_map_default_noflush(struct page *page); bool kernel_page_present(struct page *page); -void notify_range_enc_status_changed(unsigned long vaddr, int npages, bool enc); extern int kernel_set_to_readonly; diff --git a/arch/x86/include/asm/x86_init.h b/arch/x86/include/asm/x86_init.h index 22b7412c08f6..dfdcd3152f8d 100644 --- a/arch/x86/include/asm/x86_init.h +++ b/arch/x86/include/asm/x86_init.h @@ -141,6 +141,21 @@ struct x86_init_acpi { void (*reduced_hw_early_init)(void); }; +/** + * struct x86_guest - Functions used by misc guest incarnations like SEV, TDX, etc. + * + * @enc_status_change_prepare Notify HV before the encryption status of a range is changed + * @enc_status_change_finish Notify HV after the encryption status of a range is changed + * @enc_tlb_flush_required Returns true if a TLB flush is needed before changing page encryption status + * @enc_cache_flush_required Returns true if a cache flush is needed before changing page encryption status + */ +struct x86_guest { + void (*enc_status_change_prepare)(unsigned long vaddr, int npages, bool enc); + void (*enc_status_change_finish)(unsigned long vaddr, int npages, bool enc); + bool (*enc_tlb_flush_required)(bool enc); + bool (*enc_cache_flush_required)(void); +}; + /** * struct x86_init_ops - functions for platform specific setup * @@ -287,6 +302,7 @@ struct x86_platform_ops { struct x86_legacy_features legacy; void (*set_legacy_features)(void); struct x86_hyper_runtime hyper; + struct x86_guest guest; }; struct x86_apic_ops { diff --git a/arch/x86/kernel/x86_init.c b/arch/x86/kernel/x86_init.c index 7d20c1d34a3c..bb57410dde2d 100644 --- a/arch/x86/kernel/x86_init.c +++ b/arch/x86/kernel/x86_init.c @@ -129,6 +129,11 @@ struct x86_cpuinit_ops x86_cpuinit = { static void default_nmi_init(void) { }; +static void enc_status_change_prepare_noop(unsigned long vaddr, int npages, bool enc) { } +static void enc_status_change_finish_noop(unsigned long vaddr, int npages, bool enc) { } +static bool enc_tlb_flush_required_noop(bool enc) { return false; } +static bool enc_cache_flush_required_noop(void) { return false; } + struct x86_platform_ops x86_platform __ro_after_init = { .calibrate_cpu = native_calibrate_cpu_early, .calibrate_tsc = native_calibrate_tsc, @@ -138,9 +143,16 @@ struct x86_platform_ops x86_platform __ro_after_init = { .is_untracked_pat_range = is_ISA_range, .nmi_init = default_nmi_init, .get_nmi_reason = default_get_nmi_reason, - .save_sched_clock_state = tsc_save_sched_clock_state, - .restore_sched_clock_state = tsc_restore_sched_clock_state, + .save_sched_clock_state = tsc_save_sched_clock_state, + .restore_sched_clock_state = tsc_restore_sched_clock_state, .hyper.pin_vcpu = x86_op_int_noop, + + .guest = { + .enc_status_change_prepare = enc_status_change_prepare_noop, + .enc_status_change_finish = enc_status_change_finish_noop, + .enc_tlb_flush_required = enc_tlb_flush_required_noop, + .enc_cache_flush_required = enc_cache_flush_required_noop, + }, }; EXPORT_SYMBOL_GPL(x86_platform); diff --git a/arch/x86/mm/mem_encrypt_amd.c b/arch/x86/mm/mem_encrypt_amd.c index 2b2d018ea345..4c57c8988f37 100644 --- a/arch/x86/mm/mem_encrypt_amd.c +++ b/arch/x86/mm/mem_encrypt_amd.c @@ -177,25 +177,6 @@ void __init sme_map_bootdata(char *real_mode_data) __sme_early_map_unmap_mem(__va(cmdline_paddr), COMMAND_LINE_SIZE, true); } -void __init sme_early_init(void) -{ - unsigned int i; - - if (!sme_me_mask) - return; - - early_pmd_flags = __sme_set(early_pmd_flags); - - __supported_pte_mask = __sme_set(__supported_pte_mask); - - /* Update the protection map with memory encryption mask */ - for (i = 0; i < ARRAY_SIZE(protection_map); i++) - protection_map[i] = pgprot_encrypted(protection_map[i]); - - if (cc_platform_has(CC_ATTR_GUEST_MEM_ENCRYPT)) - swiotlb_force = SWIOTLB_FORCE; -} - void __init sev_setup_arch(void) { phys_addr_t total_mem = memblock_phys_mem_size(); @@ -256,7 +237,17 @@ static unsigned long pg_level_to_pfn(int level, pte_t *kpte, pgprot_t *ret_prot) return pfn; } -void notify_range_enc_status_changed(unsigned long vaddr, int npages, bool enc) +static bool amd_enc_tlb_flush_required(bool enc) +{ + return true; +} + +static bool amd_enc_cache_flush_required(void) +{ + return !cpu_feature_enabled(X86_FEATURE_SME_COHERENT); +} + +static void enc_dec_hypercall(unsigned long vaddr, int npages, bool enc) { #ifdef CONFIG_PARAVIRT unsigned long sz = npages << PAGE_SHIFT; @@ -287,6 +278,18 @@ void notify_range_enc_status_changed(unsigned long vaddr, int npages, bool enc) #endif } +static void amd_enc_status_change_prepare(unsigned long vaddr, int npages, bool enc) +{ +} + +static void amd_enc_status_change_finish(unsigned long vaddr, int npages, bool enc) +{ + if (cc_platform_has(CC_ATTR_HOST_MEM_ENCRYPT)) + return; + + enc_dec_hypercall(vaddr, npages, enc); +} + static void __init __set_clr_pte_enc(pte_t *kpte, int level, bool enc) { pgprot_t old_prot, new_prot; @@ -392,7 +395,7 @@ static int __init early_set_memory_enc_dec(unsigned long vaddr, ret = 0; - notify_range_enc_status_changed(start, PAGE_ALIGN(size) >> PAGE_SHIFT, enc); + early_set_mem_enc_dec_hypercall(start, PAGE_ALIGN(size) >> PAGE_SHIFT, enc); out: __flush_tlb_all(); return ret; @@ -410,7 +413,31 @@ int __init early_set_memory_encrypted(unsigned long vaddr, unsigned long size) void __init early_set_mem_enc_dec_hypercall(unsigned long vaddr, int npages, bool enc) { - notify_range_enc_status_changed(vaddr, npages, enc); + enc_dec_hypercall(vaddr, npages, enc); +} + +void __init sme_early_init(void) +{ + unsigned int i; + + if (!sme_me_mask) + return; + + early_pmd_flags = __sme_set(early_pmd_flags); + + __supported_pte_mask = __sme_set(__supported_pte_mask); + + /* Update the protection map with memory encryption mask */ + for (i = 0; i < ARRAY_SIZE(protection_map); i++) + protection_map[i] = pgprot_encrypted(protection_map[i]); + + if (cc_platform_has(CC_ATTR_GUEST_MEM_ENCRYPT)) + swiotlb_force = SWIOTLB_FORCE; + + x86_platform.guest.enc_status_change_prepare = amd_enc_status_change_prepare; + x86_platform.guest.enc_status_change_finish = amd_enc_status_change_finish; + x86_platform.guest.enc_tlb_flush_required = amd_enc_tlb_flush_required; + x86_platform.guest.enc_cache_flush_required = amd_enc_cache_flush_required; } void __init mem_encrypt_free_decrypted_mem(void) diff --git a/arch/x86/mm/pat/set_memory.c b/arch/x86/mm/pat/set_memory.c index af77dbfd143c..92c26828265c 100644 --- a/arch/x86/mm/pat/set_memory.c +++ b/arch/x86/mm/pat/set_memory.c @@ -2008,10 +2008,12 @@ static int __set_memory_enc_pgtable(unsigned long addr, int numpages, bool enc) kmap_flush_unused(); vm_unmap_aliases(); - /* - * Before changing the encryption attribute, we need to flush caches. - */ - cpa_flush(&cpa, !this_cpu_has(X86_FEATURE_SME_COHERENT)); + /* Flush the caches as needed before changing the encryption attribute. */ + if (x86_platform.guest.enc_tlb_flush_required(enc)) + cpa_flush(&cpa, x86_platform.guest.enc_cache_flush_required()); + + /* Notify hypervisor that we are about to set/clr encryption attribute. */ + x86_platform.guest.enc_status_change_prepare(addr, numpages, enc); ret = __change_page_attr_set_clr(&cpa, 1); @@ -2024,11 +2026,9 @@ static int __set_memory_enc_pgtable(unsigned long addr, int numpages, bool enc) */ cpa_flush(&cpa, 0); - /* - * Notify hypervisor that a given memory range is mapped encrypted - * or decrypted. - */ - notify_range_enc_status_changed(addr, numpages, enc); + /* Notify hypervisor that we have successfully set/clr encryption attribute. */ + if (!ret) + x86_platform.guest.enc_status_change_finish(addr, numpages, enc); return ret; } -- 2.29.2 -- Regards/Gruss, Boris. https://people.kernel.org/tglx/notes-about-netiquette
