From: Joerg Roedel <joro@8bytes.org> To: x86@kernel.org, Hyunwook Baek <baekhw@google.com> Cc: Joerg Roedel <joro@8bytes.org>, Joerg Roedel <jroedel@suse.de>, stable@vger.kernel.org, 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 1/6] x86/sev-es: Don't return NULL from sev_es_get_ghcb() Date: Wed, 12 May 2021 09:54:40 +0200 [thread overview] Message-ID: <20210512075445.18935-2-joro@8bytes.org> (raw) In-Reply-To: <20210512075445.18935-1-joro@8bytes.org> From: Joerg Roedel <jroedel@suse.de> The sev_es_get_ghcb() is called from several places, but only one of them checks the return value. The reaction to returning NULL is always the same: Calling panic() and kill the machine. Instead of adding checks to all call-places, move the panic() into the function itself so that it will no longer return NULL. Fixes: 0786138c78e7 ("x86/sev-es: Add a Runtime #VC Exception Handler") Cc: stable@vger.kernel.org # v5.10+ Signed-off-by: Joerg Roedel <jroedel@suse.de> --- arch/x86/kernel/sev.c | 25 ++++++++++++------------- 1 file changed, 12 insertions(+), 13 deletions(-) diff --git a/arch/x86/kernel/sev.c b/arch/x86/kernel/sev.c index 9578c82832aa..c49270c7669e 100644 --- a/arch/x86/kernel/sev.c +++ b/arch/x86/kernel/sev.c @@ -203,8 +203,18 @@ static __always_inline struct ghcb *sev_es_get_ghcb(struct ghcb_state *state) if (unlikely(data->ghcb_active)) { /* GHCB is already in use - save its contents */ - if (unlikely(data->backup_ghcb_active)) - return NULL; + if (unlikely(data->backup_ghcb_active)) { + /* + * Backup-GHCB is also already in use. There is no way + * to continue here so just kill the machine. To make + * panic() work, mark GHCBs inactive so that messages + * can be printed out. + */ + data->ghcb_active = false; + data->backup_ghcb_active = false; + + panic("Unable to handle #VC exception! GHCB and Backup GHCB are already in use"); + } /* Mark backup_ghcb active before writing to it */ data->backup_ghcb_active = true; @@ -1284,7 +1294,6 @@ static __always_inline bool on_vc_fallback_stack(struct pt_regs *regs) */ DEFINE_IDTENTRY_VC_SAFE_STACK(exc_vmm_communication) { - struct sev_es_runtime_data *data = this_cpu_read(runtime_data); irqentry_state_t irq_state; struct ghcb_state state; struct es_em_ctxt ctxt; @@ -1310,16 +1319,6 @@ DEFINE_IDTENTRY_VC_SAFE_STACK(exc_vmm_communication) */ ghcb = sev_es_get_ghcb(&state); - if (!ghcb) { - /* - * Mark GHCBs inactive so that panic() is able to print the - * message. - */ - data->ghcb_active = false; - data->backup_ghcb_active = false; - - panic("Unable to handle #VC exception! GHCB and Backup GHCB are already in use"); - } vc_ghcb_invalidate(ghcb); result = vc_init_em_ctxt(&ctxt, regs, error_code); -- 2.31.1
WARNING: multiple messages have this Message-ID (diff)
From: Joerg Roedel <joro@8bytes.org> To: x86@kernel.org, Hyunwook Baek <baekhw@google.com> 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, stable@vger.kernel.org, Masami Hiramatsu <mhiramat@kernel.org>, Erdem Aktas <erdemaktas@google.com> Subject: [PATCH 1/6] x86/sev-es: Don't return NULL from sev_es_get_ghcb() Date: Wed, 12 May 2021 09:54:40 +0200 [thread overview] Message-ID: <20210512075445.18935-2-joro@8bytes.org> (raw) In-Reply-To: <20210512075445.18935-1-joro@8bytes.org> From: Joerg Roedel <jroedel@suse.de> The sev_es_get_ghcb() is called from several places, but only one of them checks the return value. The reaction to returning NULL is always the same: Calling panic() and kill the machine. Instead of adding checks to all call-places, move the panic() into the function itself so that it will no longer return NULL. Fixes: 0786138c78e7 ("x86/sev-es: Add a Runtime #VC Exception Handler") Cc: stable@vger.kernel.org # v5.10+ Signed-off-by: Joerg Roedel <jroedel@suse.de> --- arch/x86/kernel/sev.c | 25 ++++++++++++------------- 1 file changed, 12 insertions(+), 13 deletions(-) diff --git a/arch/x86/kernel/sev.c b/arch/x86/kernel/sev.c index 9578c82832aa..c49270c7669e 100644 --- a/arch/x86/kernel/sev.c +++ b/arch/x86/kernel/sev.c @@ -203,8 +203,18 @@ static __always_inline struct ghcb *sev_es_get_ghcb(struct ghcb_state *state) if (unlikely(data->ghcb_active)) { /* GHCB is already in use - save its contents */ - if (unlikely(data->backup_ghcb_active)) - return NULL; + if (unlikely(data->backup_ghcb_active)) { + /* + * Backup-GHCB is also already in use. There is no way + * to continue here so just kill the machine. To make + * panic() work, mark GHCBs inactive so that messages + * can be printed out. + */ + data->ghcb_active = false; + data->backup_ghcb_active = false; + + panic("Unable to handle #VC exception! GHCB and Backup GHCB are already in use"); + } /* Mark backup_ghcb active before writing to it */ data->backup_ghcb_active = true; @@ -1284,7 +1294,6 @@ static __always_inline bool on_vc_fallback_stack(struct pt_regs *regs) */ DEFINE_IDTENTRY_VC_SAFE_STACK(exc_vmm_communication) { - struct sev_es_runtime_data *data = this_cpu_read(runtime_data); irqentry_state_t irq_state; struct ghcb_state state; struct es_em_ctxt ctxt; @@ -1310,16 +1319,6 @@ DEFINE_IDTENTRY_VC_SAFE_STACK(exc_vmm_communication) */ ghcb = sev_es_get_ghcb(&state); - if (!ghcb) { - /* - * Mark GHCBs inactive so that panic() is able to print the - * message. - */ - data->ghcb_active = false; - data->backup_ghcb_active = false; - - panic("Unable to handle #VC exception! GHCB and Backup GHCB are already in use"); - } vc_ghcb_invalidate(ghcb); result = vc_init_em_ctxt(&ctxt, regs, error_code); -- 2.31.1 _______________________________________________ Virtualization mailing list Virtualization@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/virtualization
next prev parent reply other threads:[~2021-05-12 7:55 UTC|newest] Thread overview: 51+ messages / expand[flat|nested] mbox.gz Atom feed top 2021-05-12 7:54 [PATCH 0/6] x86/sev-es: Fixes for SEV-ES guest support Joerg Roedel 2021-05-12 7:54 ` Joerg Roedel 2021-05-12 7:54 ` Joerg Roedel [this message] 2021-05-12 7:54 ` [PATCH 1/6] x86/sev-es: Don't return NULL from sev_es_get_ghcb() Joerg Roedel 2021-05-12 7:54 ` [PATCH 2/6] x86/sev-es: Forward page-faults which happen during emulation Joerg Roedel 2021-05-12 7:54 ` Joerg Roedel 2021-05-12 17:31 ` Sean Christopherson 2021-05-19 13:16 ` Joerg Roedel 2021-05-19 13:16 ` Joerg Roedel 2021-05-12 7:54 ` [PATCH 3/6] x86/sev-es: Use __put_user()/__get_user Joerg Roedel 2021-05-12 7:54 ` Joerg Roedel 2021-05-12 8:04 ` David Laight 2021-05-12 8:04 ` David Laight 2021-05-12 8:04 ` David Laight 2021-05-12 8:16 ` Juergen Gross 2021-05-12 8:16 ` Juergen Gross via Virtualization 2021-05-12 8:16 ` Juergen Gross 2021-05-12 8:50 ` 'Joerg Roedel' 2021-05-12 8:50 ` 'Joerg Roedel' 2021-05-12 8:50 ` 'Joerg Roedel' 2021-05-12 8:58 ` Juergen Gross 2021-05-12 8:58 ` Juergen Gross via Virtualization 2021-05-12 8:58 ` Juergen Gross 2021-05-12 9:31 ` David Laight 2021-05-12 9:31 ` David Laight 2021-05-12 9:31 ` David Laight 2021-05-12 9:32 ` Joerg Roedel 2021-05-12 9:32 ` Joerg Roedel 2021-05-12 9:32 ` Joerg Roedel 2021-05-19 11:33 ` 'Joerg Roedel' 2021-05-19 11:33 ` 'Joerg Roedel' 2021-05-19 11:33 ` 'Joerg Roedel' 2021-05-12 8:37 ` 'Joerg Roedel' 2021-05-12 8:37 ` 'Joerg Roedel' 2021-05-12 8:37 ` 'Joerg Roedel' 2021-05-12 15:59 ` Dave Hansen 2021-05-12 15:59 ` Dave Hansen 2021-05-12 15:59 ` Dave Hansen 2021-05-12 15:57 ` Dave Hansen 2021-05-12 15:57 ` Dave Hansen 2021-05-12 16:00 ` Joerg Roedel 2021-05-12 16:00 ` Joerg Roedel 2021-05-12 7:54 ` [PATCH 4/6] Revert "x86/sev-es: Handle string port IO to kernel memory properly" Joerg Roedel 2021-05-12 7:54 ` Joerg Roedel 2021-05-12 17:38 ` Sean Christopherson 2021-05-19 12:22 ` Joerg Roedel 2021-05-19 12:22 ` Joerg Roedel 2021-05-12 7:54 ` [PATCH 5/6] x86/sev-es: Fix error message in runtime #VC handler Joerg Roedel 2021-05-12 7:54 ` Joerg Roedel 2021-05-12 7:54 ` [PATCH 6/6] x86/sev-es: Leave NMI-mode before sending signals Joerg Roedel 2021-05-12 7:54 ` Joerg Roedel
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