linux-kernel - [PATCH kernel 3/3] x86/sev: Do not handle #VC for DR7 read/write

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20221201021948.9259-4-aik@amd.com>
Date:   Thu, 1 Dec 2022 13:19:48 +1100
From:   Alexey Kardashevskiy <aik@....com>
To:     Alexey Kardashevskiy <aik@....com>
CC:     <kvm@...r.kernel.org>, <x86@...nel.org>,
        <linux-kernel@...r.kernel.org>,
        Venu Busireddy <venu.busireddy@...cle.com>,
        Tony Luck <tony.luck@...el.com>,
        Tom Lendacky <thomas.lendacky@....com>,
        Thomas Gleixner <tglx@...utronix.de>,
        Sean Christopherson <seanjc@...gle.com>,
        Peter Zijlstra <peterz@...radead.org>,
        Paolo Bonzini <pbonzini@...hat.com>,
        Michael Sterritt <sterritt@...gle.com>,
        Michael Roth <michael.roth@....com>,
        Mario Limonciello <mario.limonciello@....com>,
        Ingo Molnar <mingo@...hat.com>,
        Heiko Carstens <hca@...ux.ibm.com>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        "Dave Hansen" <dave.hansen@...ux.intel.com>,
        Borislav Petkov <bp@...en8.de>,
        "Andrew Cooper" <andrew.cooper3@...rix.com>,
        "Jason A. Donenfeld" <Jason@...c4.com>,
        "H. Peter Anvin" <hpa@...or.com>
Subject: [PATCH kernel 3/3] x86/sev: Do not handle #VC for DR7 read/write

With SVM_SEV_FEAT_DEBUG_SWAP enabled, the VM should not get #VC events
for DR7 read/write which it rather avoided.

Signed-off-by: Alexey Kardashevskiy <aik@....com>
---
 arch/x86/kernel/sev.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/arch/x86/kernel/sev.c b/arch/x86/kernel/sev.c
index a428c62330d3..4e91b9f8742c 100644
--- a/arch/x86/kernel/sev.c
+++ b/arch/x86/kernel/sev.c
@@ -1618,6 +1618,9 @@ static enum es_result vc_handle_dr7_write(struct ghcb *ghcb,
 	long val, *reg = vc_insn_get_rm(ctxt);
 	enum es_result ret;
 
+	if ((sev_status >> 2) & SVM_SEV_FEAT_DEBUG_SWAP)
+		return ES_VMM_ERROR;
+
 	if (!reg)
 		return ES_DECODE_FAILED;
 
@@ -1655,6 +1658,9 @@ static enum es_result vc_handle_dr7_read(struct ghcb *ghcb,
 	struct sev_es_runtime_data *data = this_cpu_read(runtime_data);
 	long *reg = vc_insn_get_rm(ctxt);
 
+	if ((sev_status >> 2) & SVM_SEV_FEAT_DEBUG_SWAP)
+		return ES_VMM_ERROR;
+
 	if (!reg)
 		return ES_DECODE_FAILED;
 
-- 
2.38.1