From mboxrd@z Thu Jan 1 00:00:00 1970 From: Joerg Roedel Subject: [PATCH 46/70] x86/sev-es: Filter exceptions not supported from user-space Date: Thu, 19 Mar 2020 10:13:43 +0100 Message-ID: <20200319091407.1481-47-joro@8bytes.org> References: <20200319091407.1481-1-joro@8bytes.org> Return-path: In-Reply-To: <20200319091407.1481-1-joro@8bytes.org> Sender: linux-kernel-owner@vger.kernel.org To: x86@kernel.org Cc: hpa@zytor.com, Andy Lutomirski , Dave Hansen , Peter Zijlstra , Thomas Hellstrom , Jiri Slaby , Dan Williams , Tom Lendacky , Juergen Gross , Kees Cook , linux-kernel@vger.kernel.org, kvm@vger.kernel.org, virtualization@lists.linux-foundation.org, Joerg Roedel , Joerg Roedel List-Id: virtualization@lists.linuxfoundation.org From: Joerg Roedel Currently only CPUID caused #VC exceptions are supported from user-space. Filter the others out early. Signed-off-by: Joerg Roedel --- arch/x86/kernel/sev-es.c | 24 ++++++++++++++++++++++++ 1 file changed, 24 insertions(+) diff --git a/arch/x86/kernel/sev-es.c b/arch/x86/kernel/sev-es.c index 71eee7b3667d..6d45a2499460 100644 --- a/arch/x86/kernel/sev-es.c +++ b/arch/x86/kernel/sev-es.c @@ -318,6 +318,26 @@ static enum es_result vc_handle_exitcode(struct es_em_ctxt *ctxt, return result; } +static enum es_result vc_context_filter(struct pt_regs *regs, long exit_code) +{ + enum es_result r = ES_OK; + + if (user_mode(regs)) { + switch (exit_code) { + /* List of #VC exit-codes we support in user-space */ + case SVM_EXIT_EXCP_BASE ... SVM_EXIT_LAST_EXCP: + case SVM_EXIT_CPUID: + r = ES_OK; + break; + default: + r = ES_UNSUPPORTED; + break; + } + } + + return r; +} + static void vc_forward_exception(struct es_em_ctxt *ctxt) { long error_code = ctxt->fi.error_code; @@ -359,6 +379,10 @@ dotraplinkage void do_vmm_communication(struct pt_regs *regs, unsigned long exit result = vc_init_em_ctxt(&ctxt, regs, exit_code); } + /* Check if the exception is supported in the context we came from. */ + if (result == ES_OK) + result = vc_context_filter(regs, exit_code); + if (result == ES_OK) result = vc_handle_exitcode(&ctxt, ghcb, exit_code); -- 2.17.1