From 871808fd6981bcc6bb48f71032f983ca77748e96 Mon Sep 17 00:00:00 2001 From: Lukas Bulwahn Date: Fri, 22 Jul 2022 14:18:15 +0200 Subject: [PATCH 1/4] x86/configs: Update configs in x86_debug.config Commit 4675ff05de2d ("kmemcheck: rip it out") removed kmemcheck and its corresponding build config KMEMCHECK. Commit 0f620cefd775 ("objtool: Rename "VMLINUX_VALIDATION" -> "NOINSTR_VALIDATION"") renamed the debug config option. Adjust x86_debug.config to those changes in debug configs. Signed-off-by: Lukas Bulwahn Signed-off-by: Borislav Petkov Link: https://lore.kernel.org/r/20220722121815.27535-1-lukas.bulwahn@gmail.com --- kernel/configs/x86_debug.config | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) diff --git a/kernel/configs/x86_debug.config b/kernel/configs/x86_debug.config index dcd86f32f4ed..6fac5b405334 100644 --- a/kernel/configs/x86_debug.config +++ b/kernel/configs/x86_debug.config @@ -7,12 +7,11 @@ CONFIG_DEBUG_SLAB=y CONFIG_DEBUG_KMEMLEAK=y CONFIG_DEBUG_PAGEALLOC=y CONFIG_SLUB_DEBUG_ON=y -CONFIG_KMEMCHECK=y CONFIG_DEBUG_OBJECTS=y CONFIG_DEBUG_OBJECTS_ENABLE_DEFAULT=1 CONFIG_GCOV_KERNEL=y CONFIG_LOCKDEP=y CONFIG_PROVE_LOCKING=y CONFIG_SCHEDSTATS=y -CONFIG_VMLINUX_VALIDATION=y +CONFIG_NOINSTR_VALIDATION=y CONFIG_DEBUG_INFO_DWARF_TOOLCHAIN_DEFAULT=y From 5bb6c1d1126ebcbcd6314f80d82f50b021a9e351 Mon Sep 17 00:00:00 2001 From: Borislav Petkov Date: Wed, 27 Jul 2022 13:24:21 +0200 Subject: [PATCH 2/4] Revert "x86/sev: Expose sev_es_ghcb_hv_call() for use by HyperV" MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit This reverts commit 007faec014cb5d26983c1f86fd08c6539b41392e. Now that hyperv does its own protocol negotiation: 49d6a3c062a1 ("x86/Hyper-V: Add SEV negotiate protocol support in Isolation VM") revert this exposure of the sev_es_ghcb_hv_call() helper. Cc: Wei Liu Signed-off-by: Borislav Petkov Reviewed-by：Tianyu Lan Link: https://lore.kernel.org/r/20220614014553.1915929-1-ltykernel@gmail.com --- arch/x86/include/asm/sev.h | 7 +------ arch/x86/kernel/sev-shared.c | 25 +++++++++---------------- arch/x86/kernel/sev.c | 17 ++++++++--------- 3 files changed, 18 insertions(+), 31 deletions(-) diff --git a/arch/x86/include/asm/sev.h b/arch/x86/include/asm/sev.h index 19514524f0f8..4a23e52fe0ee 100644 --- a/arch/x86/include/asm/sev.h +++ b/arch/x86/include/asm/sev.h @@ -72,7 +72,6 @@ static inline u64 lower_bits(u64 val, unsigned int bits) struct real_mode_header; enum stack_type; -struct ghcb; /* Early IDT entry points for #VC handler */ extern void vc_no_ghcb(void); @@ -156,11 +155,7 @@ static __always_inline void sev_es_nmi_complete(void) __sev_es_nmi_complete(); } extern int __init sev_es_efi_map_ghcbs(pgd_t *pgd); -extern enum es_result sev_es_ghcb_hv_call(struct ghcb *ghcb, - bool set_ghcb_msr, - struct es_em_ctxt *ctxt, - u64 exit_code, u64 exit_info_1, - u64 exit_info_2); + static inline int rmpadjust(unsigned long vaddr, bool rmp_psize, unsigned long attrs) { int rc; diff --git a/arch/x86/kernel/sev-shared.c b/arch/x86/kernel/sev-shared.c index b478edf43bec..3a5b0c9c4fcc 100644 --- a/arch/x86/kernel/sev-shared.c +++ b/arch/x86/kernel/sev-shared.c @@ -219,9 +219,10 @@ static enum es_result verify_exception_info(struct ghcb *ghcb, struct es_em_ctxt return ES_VMM_ERROR; } -enum es_result sev_es_ghcb_hv_call(struct ghcb *ghcb, bool set_ghcb_msr, - struct es_em_ctxt *ctxt, u64 exit_code, - u64 exit_info_1, u64 exit_info_2) +static enum es_result sev_es_ghcb_hv_call(struct ghcb *ghcb, + struct es_em_ctxt *ctxt, + u64 exit_code, u64 exit_info_1, + u64 exit_info_2) { /* Fill in protocol and format specifiers */ ghcb->protocol_version = ghcb_version; @@ -231,14 +232,7 @@ enum es_result sev_es_ghcb_hv_call(struct ghcb *ghcb, bool set_ghcb_msr, ghcb_set_sw_exit_info_1(ghcb, exit_info_1); ghcb_set_sw_exit_info_2(ghcb, exit_info_2); - /* - * Hyper-V unenlightened guests use a paravisor for communicating and - * GHCB pages are being allocated and set up by that paravisor. Linux - * should not change the GHCB page's physical address. - */ - if (set_ghcb_msr) - sev_es_wr_ghcb_msr(__pa(ghcb)); - + sev_es_wr_ghcb_msr(__pa(ghcb)); VMGEXIT(); return verify_exception_info(ghcb, ctxt); @@ -795,7 +789,7 @@ static enum es_result vc_handle_ioio(struct ghcb *ghcb, struct es_em_ctxt *ctxt) */ sw_scratch = __pa(ghcb) + offsetof(struct ghcb, shared_buffer); ghcb_set_sw_scratch(ghcb, sw_scratch); - ret = sev_es_ghcb_hv_call(ghcb, true, ctxt, SVM_EXIT_IOIO, + ret = sev_es_ghcb_hv_call(ghcb, ctxt, SVM_EXIT_IOIO, exit_info_1, exit_info_2); if (ret != ES_OK) return ret; @@ -837,8 +831,7 @@ static enum es_result vc_handle_ioio(struct ghcb *ghcb, struct es_em_ctxt *ctxt) ghcb_set_rax(ghcb, rax); - ret = sev_es_ghcb_hv_call(ghcb, true, ctxt, - SVM_EXIT_IOIO, exit_info_1, 0); + ret = sev_es_ghcb_hv_call(ghcb, ctxt, SVM_EXIT_IOIO, exit_info_1, 0); if (ret != ES_OK) return ret; @@ -894,7 +887,7 @@ static enum es_result vc_handle_cpuid(struct ghcb *ghcb, /* xgetbv will cause #GP - use reset value for xcr0 */ ghcb_set_xcr0(ghcb, 1); - ret = sev_es_ghcb_hv_call(ghcb, true, ctxt, SVM_EXIT_CPUID, 0, 0); + ret = sev_es_ghcb_hv_call(ghcb, ctxt, SVM_EXIT_CPUID, 0, 0); if (ret != ES_OK) return ret; @@ -919,7 +912,7 @@ static enum es_result vc_handle_rdtsc(struct ghcb *ghcb, bool rdtscp = (exit_code == SVM_EXIT_RDTSCP); enum es_result ret; - ret = sev_es_ghcb_hv_call(ghcb, true, ctxt, exit_code, 0, 0); + ret = sev_es_ghcb_hv_call(ghcb, ctxt, exit_code, 0, 0); if (ret != ES_OK) return ret; diff --git a/arch/x86/kernel/sev.c b/arch/x86/kernel/sev.c index c05f0124c410..63dc626627a0 100644 --- a/arch/x86/kernel/sev.c +++ b/arch/x86/kernel/sev.c @@ -786,7 +786,7 @@ static int vmgexit_psc(struct snp_psc_desc *desc) ghcb_set_sw_scratch(ghcb, (u64)__pa(data)); /* This will advance the shared buffer data points to. */ - ret = sev_es_ghcb_hv_call(ghcb, true, &ctxt, SVM_VMGEXIT_PSC, 0, 0); + ret = sev_es_ghcb_hv_call(ghcb, &ctxt, SVM_VMGEXIT_PSC, 0, 0); /* * Page State Change VMGEXIT can pass error code through @@ -1212,8 +1212,7 @@ static enum es_result vc_handle_msr(struct ghcb *ghcb, struct es_em_ctxt *ctxt) ghcb_set_rdx(ghcb, regs->dx); } - ret = sev_es_ghcb_hv_call(ghcb, true, ctxt, SVM_EXIT_MSR, - exit_info_1, 0); + ret = sev_es_ghcb_hv_call(ghcb, ctxt, SVM_EXIT_MSR, exit_info_1, 0); if ((ret == ES_OK) && (!exit_info_1)) { regs->ax = ghcb->save.rax; @@ -1452,7 +1451,7 @@ static enum es_result vc_do_mmio(struct ghcb *ghcb, struct es_em_ctxt *ctxt, ghcb_set_sw_scratch(ghcb, ghcb_pa + offsetof(struct ghcb, shared_buffer)); - return sev_es_ghcb_hv_call(ghcb, true, ctxt, exit_code, exit_info_1, exit_info_2); + return sev_es_ghcb_hv_call(ghcb, ctxt, exit_code, exit_info_1, exit_info_2); } /* @@ -1628,7 +1627,7 @@ static enum es_result vc_handle_dr7_write(struct ghcb *ghcb, /* Using a value of 0 for ExitInfo1 means RAX holds the value */ ghcb_set_rax(ghcb, val); - ret = sev_es_ghcb_hv_call(ghcb, true, ctxt, SVM_EXIT_WRITE_DR7, 0, 0); + ret = sev_es_ghcb_hv_call(ghcb, ctxt, SVM_EXIT_WRITE_DR7, 0, 0); if (ret != ES_OK) return ret; @@ -1658,7 +1657,7 @@ static enum es_result vc_handle_dr7_read(struct ghcb *ghcb, static enum es_result vc_handle_wbinvd(struct ghcb *ghcb, struct es_em_ctxt *ctxt) { - return sev_es_ghcb_hv_call(ghcb, true, ctxt, SVM_EXIT_WBINVD, 0, 0); + return sev_es_ghcb_hv_call(ghcb, ctxt, SVM_EXIT_WBINVD, 0, 0); } static enum es_result vc_handle_rdpmc(struct ghcb *ghcb, struct es_em_ctxt *ctxt) @@ -1667,7 +1666,7 @@ static enum es_result vc_handle_rdpmc(struct ghcb *ghcb, struct es_em_ctxt *ctxt ghcb_set_rcx(ghcb, ctxt->regs->cx); - ret = sev_es_ghcb_hv_call(ghcb, true, ctxt, SVM_EXIT_RDPMC, 0, 0); + ret = sev_es_ghcb_hv_call(ghcb, ctxt, SVM_EXIT_RDPMC, 0, 0); if (ret != ES_OK) return ret; @@ -1708,7 +1707,7 @@ static enum es_result vc_handle_vmmcall(struct ghcb *ghcb, if (x86_platform.hyper.sev_es_hcall_prepare) x86_platform.hyper.sev_es_hcall_prepare(ghcb, ctxt->regs); - ret = sev_es_ghcb_hv_call(ghcb, true, ctxt, SVM_EXIT_VMMCALL, 0, 0); + ret = sev_es_ghcb_hv_call(ghcb, ctxt, SVM_EXIT_VMMCALL, 0, 0); if (ret != ES_OK) return ret; @@ -2197,7 +2196,7 @@ int snp_issue_guest_request(u64 exit_code, struct snp_req_data *input, unsigned ghcb_set_rbx(ghcb, input->data_npages); } - ret = sev_es_ghcb_hv_call(ghcb, true, &ctxt, exit_code, input->req_gpa, input->resp_gpa); + ret = sev_es_ghcb_hv_call(ghcb, &ctxt, exit_code, input->req_gpa, input->resp_gpa); if (ret) goto e_put; From 571c30b1a88465a1c85a6f7762609939b9085a15 Mon Sep 17 00:00:00 2001 From: Thadeu Lima de Souza Cascardo Date: Thu, 28 Jul 2022 09:26:02 -0300 Subject: [PATCH 3/4] x86/bugs: Do not enable IBPB at firmware entry when IBPB is not available Some cloud hypervisors do not provide IBPB on very recent CPU processors, including AMD processors affected by Retbleed. Using IBPB before firmware calls on such systems would cause a GPF at boot like the one below. Do not enable such calls when IBPB support is not present. EFI Variables Facility v0.08 2004-May-17 general protection fault, maybe for address 0x1: 0000 [#1] PREEMPT SMP NOPTI CPU: 0 PID: 24 Comm: kworker/u2:1 Not tainted 5.19.0-rc8+ #7 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 0.0.0 02/06/2015 Workqueue: efi_rts_wq efi_call_rts RIP: 0010:efi_call_rts Code: e8 37 33 58 ff 41 bf 48 00 00 00 49 89 c0 44 89 f9 48 83 c8 01 4c 89 c2 48 c1 ea 20 66 90 b9 49 00 00 00 b8 01 00 00 00 31 d2 <0f> 30 e8 7b 9f 5d ff e8 f6 f8 ff ff 4c 89 f1 4c 89 ea 4c 89 e6 48 RSP: 0018:ffffb373800d7e38 EFLAGS: 00010246 RAX: 0000000000000001 RBX: 0000000000000006 RCX: 0000000000000049 RDX: 0000000000000000 RSI: ffff94fbc19d8fe0 RDI: ffff94fbc1b2b300 RBP: ffffb373800d7e70 R08: 0000000000000000 R09: 0000000000000000 R10: 000000000000000b R11: 000000000000000b R12: ffffb3738001fd78 R13: ffff94fbc2fcfc00 R14: ffffb3738001fd80 R15: 0000000000000048 FS: 0000000000000000(0000) GS:ffff94fc3da00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: ffff94fc30201000 CR3: 000000006f610000 CR4: 00000000000406f0 Call Trace: ? __wake_up process_one_work worker_thread ? rescuer_thread kthread ? kthread_complete_and_exit ret_from_fork Modules linked in: Fixes: 28a99e95f55c ("x86/amd: Use IBPB for firmware calls") Reported-by: Dimitri John Ledkov Signed-off-by: Thadeu Lima de Souza Cascardo Signed-off-by: Borislav Petkov Cc: Link: https://lore.kernel.org/r/20220728122602.2500509-1-cascardo@canonical.com --- arch/x86/kernel/cpu/bugs.c | 1 + 1 file changed, 1 insertion(+) diff --git a/arch/x86/kernel/cpu/bugs.c b/arch/x86/kernel/cpu/bugs.c index 6454bc767f0f..6761668100b9 100644 --- a/arch/x86/kernel/cpu/bugs.c +++ b/arch/x86/kernel/cpu/bugs.c @@ -1520,6 +1520,7 @@ static void __init spectre_v2_select_mitigation(void) * enable IBRS around firmware calls. */ if (boot_cpu_has_bug(X86_BUG_RETBLEED) && + boot_cpu_has(X86_FEATURE_IBPB) && (boot_cpu_data.x86_vendor == X86_VENDOR_AMD || boot_cpu_data.x86_vendor == X86_VENDOR_HYGON)) { From ea304a8b89fd0d6cf94ee30cb139dc23d9f1a62f Mon Sep 17 00:00:00 2001 From: Eiichi Tsukata Date: Thu, 28 Jul 2022 04:39:07 +0000 Subject: [PATCH 4/4] docs/kernel-parameters: Update descriptions for "mitigations=" param with retbleed Updates descriptions for "mitigations=off" and "mitigations=auto,nosmt" with the respective retbleed= settings. Signed-off-by: Eiichi Tsukata Signed-off-by: Borislav Petkov Cc: corbet@lwn.net Link: https://lore.kernel.org/r/20220728043907.165688-1-eiichi.tsukata@nutanix.com --- Documentation/admin-guide/kernel-parameters.txt | 2 ++ 1 file changed, 2 insertions(+) diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index c0fdb04a0435..cc3ea8febc62 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -3176,6 +3176,7 @@ no_entry_flush [PPC] no_uaccess_flush [PPC] mmio_stale_data=off [X86] + retbleed=off [X86] Exceptions: This does not have any effect on @@ -3198,6 +3199,7 @@ mds=full,nosmt [X86] tsx_async_abort=full,nosmt [X86] mmio_stale_data=full,nosmt [X86] + retbleed=auto,nosmt [X86] mminit_loglevel= [KNL] When CONFIG_DEBUG_MEMORY_INIT is set, this