linux-kernel - [PATCH v3 1/2] KVM: arm64: Allow userspace to change ID_AA64PFR1

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: <20240628060454.1936886-2-shahuang@redhat.com>
Date: Fri, 28 Jun 2024 02:04:51 -0400
From: Shaoqin Huang <shahuang@...hat.com>
To: Oliver Upton <oliver.upton@...ux.dev>,
	Marc Zyngier <maz@...nel.org>,
	kvmarm@...ts.linux.dev
Cc: Shaoqin Huang <shahuang@...hat.com>,
	James Morse <james.morse@....com>,
	Suzuki K Poulose <suzuki.poulose@....com>,
	Zenghui Yu <yuzenghui@...wei.com>,
	Catalin Marinas <catalin.marinas@....com>,
	Will Deacon <will@...nel.org>,
	linux-arm-kernel@...ts.infradead.org,
	linux-kernel@...r.kernel.org
Subject: [PATCH v3 1/2] KVM: arm64: Allow userspace to change ID_AA64PFR1_EL1

Allow userspace to change the guest-visible value of the register with
some severe limitation:

  - No changes to features not virtualized by KVM (MPAM_frac, RAS_frac,
    SME, RNDP_trap).

  - No changes to features (CSV2_frac, NMI, MTE_frac, GCS, THE, MTEX,
    DF2, PFAR) which haven't been added into the ftr_id_aa64pfr1[].
    Because the struct arm64_ftr_bits definition for each feature in the
    ftr_id_aa64pfr1[] is used by arm64_check_features. If they're not
    existing in the ftr_id_aa64pfr1[], the for loop won't check the if
    the new_val is safe for those features.
---
 arch/arm64/kvm/sys_regs.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
index 22b45a15d068..159cded22357 100644
--- a/arch/arm64/kvm/sys_regs.c
+++ b/arch/arm64/kvm/sys_regs.c
@@ -2306,7 +2306,9 @@ static const struct sys_reg_desc sys_reg_descs[] = {
 		   ID_AA64PFR0_EL1_GIC |
 		   ID_AA64PFR0_EL1_AdvSIMD |
 		   ID_AA64PFR0_EL1_FP), },
-	ID_SANITISED(ID_AA64PFR1_EL1),
+	ID_WRITABLE(ID_AA64PFR1_EL1, ID_AA64PFR1_EL1_MTE |
+				     ID_AA64PFR1_EL1_SSBS |
+				     ID_AA64PFR1_EL1_BT),
 	ID_UNALLOCATED(4,2),
 	ID_UNALLOCATED(4,3),
 	ID_WRITABLE(ID_AA64ZFR0_EL1, ~ID_AA64ZFR0_EL1_RES0),
-- 
2.40.1