From: Joerg Roedel <joro@8bytes.org> To: x86@kernel.org Cc: Joerg Roedel <joro@8bytes.org>, Joerg Roedel <jroedel@suse.de>, hpa@zytor.com, Andy Lutomirski <luto@kernel.org>, Dave Hansen <dave.hansen@linux.intel.com>, Peter Zijlstra <peterz@infradead.org>, Jiri Slaby <jslaby@suse.cz>, Dan Williams <dan.j.williams@intel.com>, Tom Lendacky <thomas.lendacky@amd.com>, Juergen Gross <jgross@suse.com>, Kees Cook <keescook@chromium.org>, David Rientjes <rientjes@google.com>, Cfir Cohen <cfir@google.com>, Erdem Aktas <erdemaktas@google.com>, Masami Hiramatsu <mhiramat@kernel.org>, Mike Stunes <mstunes@vmware.com>, Sean Christopherson <seanjc@google.com>, Martin Radev <martin.b.radev@gmail.com>, Arvind Sankar <nivedita@alum.mit.edu>, linux-coco@lists.linux.dev, linux-kernel@vger.kernel.org, kvm@vger.kernel.org, virtualization@lists.linux-foundation.org Subject: [PATCH v3 7/7] x86/sev-es: Propagate #GP if getting linear instruction address failed Date: Tue, 8 Jun 2021 11:54:39 +0200 [thread overview] Message-ID: <20210608095439.12668-8-joro@8bytes.org> (raw) In-Reply-To: <20210608095439.12668-1-joro@8bytes.org> From: Joerg Roedel <jroedel@suse.de> When an instruction is fetched from user-space, segmentation needs to be taken into account. This means that getting the linear address of an instruction can fail. Hardware would raise a #GP exception in that case, but the #VC exception handler would emulate it as a page-fault. The insn_fetch_from_user*() functions now provide the relevant information in case of an failure. Use that and propagate a #GP when the linear address of an instruction to fetch could not be calculated. Signed-off-by: Joerg Roedel <jroedel@suse.de> --- arch/x86/kernel/sev.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) diff --git a/arch/x86/kernel/sev.c b/arch/x86/kernel/sev.c index 2b499affb2fb..737d7198aab1 100644 --- a/arch/x86/kernel/sev.c +++ b/arch/x86/kernel/sev.c @@ -270,11 +270,18 @@ static enum es_result __vc_decode_user_insn(struct es_em_ctxt *ctxt) int insn_bytes; insn_bytes = insn_fetch_from_user_inatomic(ctxt->regs, buffer); - if (insn_bytes <= 0) { + if (insn_bytes == 0) { + /* Nothing could be copied */ ctxt->fi.vector = X86_TRAP_PF; ctxt->fi.error_code = X86_PF_INSTR | X86_PF_USER; ctxt->fi.cr2 = ctxt->regs->ip; return ES_EXCEPTION; + } else if (insn_bytes == -EINVAL) { + /* Effective RIP could not be calculated */ + ctxt->fi.vector = X86_TRAP_GP; + ctxt->fi.error_code = 0; + ctxt->fi.cr2 = 0; + return ES_EXCEPTION; } if (!insn_decode_from_regs(&ctxt->insn, ctxt->regs, buffer, insn_bytes)) -- 2.31.1
WARNING: multiple messages have this Message-ID (diff)
From: Joerg Roedel <joro@8bytes.org> To: x86@kernel.org Cc: kvm@vger.kernel.org, Peter Zijlstra <peterz@infradead.org>, Dave Hansen <dave.hansen@linux.intel.com>, virtualization@lists.linux-foundation.org, Arvind Sankar <nivedita@alum.mit.edu>, hpa@zytor.com, Jiri Slaby <jslaby@suse.cz>, Joerg Roedel <joro@8bytes.org>, David Rientjes <rientjes@google.com>, Martin Radev <martin.b.radev@gmail.com>, Tom Lendacky <thomas.lendacky@amd.com>, Joerg Roedel <jroedel@suse.de>, Kees Cook <keescook@chromium.org>, Cfir Cohen <cfir@google.com>, linux-coco@lists.linux.dev, Andy Lutomirski <luto@kernel.org>, Dan Williams <dan.j.williams@intel.com>, Juergen Gross <jgross@suse.com>, Mike Stunes <mstunes@vmware.com>, Sean Christopherson <seanjc@google.com>, linux-kernel@vger.kernel.org, Masami Hiramatsu <mhiramat@kernel.org>, Erdem Aktas <erdemaktas@google.com> Subject: [PATCH v3 7/7] x86/sev-es: Propagate #GP if getting linear instruction address failed Date: Tue, 8 Jun 2021 11:54:39 +0200 [thread overview] Message-ID: <20210608095439.12668-8-joro@8bytes.org> (raw) In-Reply-To: <20210608095439.12668-1-joro@8bytes.org> From: Joerg Roedel <jroedel@suse.de> When an instruction is fetched from user-space, segmentation needs to be taken into account. This means that getting the linear address of an instruction can fail. Hardware would raise a #GP exception in that case, but the #VC exception handler would emulate it as a page-fault. The insn_fetch_from_user*() functions now provide the relevant information in case of an failure. Use that and propagate a #GP when the linear address of an instruction to fetch could not be calculated. Signed-off-by: Joerg Roedel <jroedel@suse.de> --- arch/x86/kernel/sev.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) diff --git a/arch/x86/kernel/sev.c b/arch/x86/kernel/sev.c index 2b499affb2fb..737d7198aab1 100644 --- a/arch/x86/kernel/sev.c +++ b/arch/x86/kernel/sev.c @@ -270,11 +270,18 @@ static enum es_result __vc_decode_user_insn(struct es_em_ctxt *ctxt) int insn_bytes; insn_bytes = insn_fetch_from_user_inatomic(ctxt->regs, buffer); - if (insn_bytes <= 0) { + if (insn_bytes == 0) { + /* Nothing could be copied */ ctxt->fi.vector = X86_TRAP_PF; ctxt->fi.error_code = X86_PF_INSTR | X86_PF_USER; ctxt->fi.cr2 = ctxt->regs->ip; return ES_EXCEPTION; + } else if (insn_bytes == -EINVAL) { + /* Effective RIP could not be calculated */ + ctxt->fi.vector = X86_TRAP_GP; + ctxt->fi.error_code = 0; + ctxt->fi.cr2 = 0; + return ES_EXCEPTION; } if (!insn_decode_from_regs(&ctxt->insn, ctxt->regs, buffer, insn_bytes)) -- 2.31.1 _______________________________________________ Virtualization mailing list Virtualization@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/virtualization
next prev parent reply other threads:[~2021-06-08 9:54 UTC|newest] Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top 2021-06-08 9:54 [PATCH v3 0/7] x86/sev-es: Fixes for SEV-ES Guest Support Joerg Roedel 2021-06-08 9:54 ` Joerg Roedel 2021-06-08 9:54 ` [PATCH v3 1/7] x86/ioremap: Map efi_mem_reserve() memory as encrypted for SEV Joerg Roedel 2021-06-08 9:54 ` Joerg Roedel 2021-06-08 15:26 ` [tip: x86/urgent] x86/ioremap: Map EFI-reserved " tip-bot2 for Tom Lendacky 2021-06-08 9:54 ` [PATCH v3 2/7] x86/sev-es: Fix error message in runtime #VC handler Joerg Roedel 2021-06-08 9:54 ` Joerg Roedel 2021-06-08 9:54 ` [PATCH v3 3/7] x86/sev-es: Disable IRQs while GHCB is active Joerg Roedel 2021-06-08 9:54 ` Joerg Roedel 2021-06-08 9:54 ` [PATCH v3 4/7] x86/sev-es: Run #VC handler in plain IRQ state Joerg Roedel 2021-06-08 9:54 ` Joerg Roedel 2021-06-08 11:58 ` Peter Zijlstra 2021-06-08 11:58 ` Peter Zijlstra 2021-06-08 13:25 ` Joerg Roedel 2021-06-08 13:25 ` Joerg Roedel 2021-06-08 9:54 ` [PATCH v3 5/7] x86/insn-eval: Make 0 a valid RIP for insn_get_effective_ip() Joerg Roedel 2021-06-08 9:54 ` Joerg Roedel 2021-06-08 9:54 ` [PATCH v3 6/7] x86/insn: Extend error reporting from insn_fetch_from_user[_inatomic]() Joerg Roedel 2021-06-08 9:54 ` Joerg Roedel 2021-06-08 9:54 ` Joerg Roedel [this message] 2021-06-08 9:54 ` [PATCH v3 7/7] x86/sev-es: Propagate #GP if getting linear instruction address failed Joerg Roedel
Reply instructions: You may reply publicly to this message via plain-text email using any one of the following methods: * Save the following mbox file, import it into your mail client, and reply-to-all from there: mbox Avoid top-posting and favor interleaved quoting: https://en.wikipedia.org/wiki/Posting_style#Interleaved_style * Reply using the --to, --cc, and --in-reply-to switches of git-send-email(1): git send-email \ --in-reply-to=20210608095439.12668-8-joro@8bytes.org \ --to=joro@8bytes.org \ --cc=cfir@google.com \ --cc=dan.j.williams@intel.com \ --cc=dave.hansen@linux.intel.com \ --cc=erdemaktas@google.com \ --cc=hpa@zytor.com \ --cc=jgross@suse.com \ --cc=jroedel@suse.de \ --cc=jslaby@suse.cz \ --cc=keescook@chromium.org \ --cc=kvm@vger.kernel.org \ --cc=linux-coco@lists.linux.dev \ --cc=linux-kernel@vger.kernel.org \ --cc=luto@kernel.org \ --cc=martin.b.radev@gmail.com \ --cc=mhiramat@kernel.org \ --cc=mstunes@vmware.com \ --cc=nivedita@alum.mit.edu \ --cc=peterz@infradead.org \ --cc=rientjes@google.com \ --cc=seanjc@google.com \ --cc=thomas.lendacky@amd.com \ --cc=virtualization@lists.linux-foundation.org \ --cc=x86@kernel.org \ /path/to/YOUR_REPLY https://kernel.org/pub/software/scm/git/docs/git-send-email.html * If your mail client supports setting the In-Reply-To header via mailto: links, try the mailto: linkBe sure your reply has a Subject: header at the top and a blank line before the message body.
This is an external index of several public inboxes, see mirroring instructions on how to clone and mirror all data and code used by this external index.