linux-kernel - [PATCH] KVM: PPC: Add the missing character/behaviour bits for KVM_PPC_GET_CPU

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>] [day] [month] [year] [list]

Message-ID: <20251203132804.16692-1-gautam@linux.ibm.com>
Date: Wed,  3 Dec 2025 18:58:03 +0530
From: Gautam Menghani <gautam@...ux.ibm.com>
To: maddy@...ux.ibm.com, vaibhav@...il.com, npiggin@...il.com,
        mpe@...erman.id.au, christophe.leroy@...roup.eu
Cc: Gautam Menghani <gautam@...ux.ibm.com>, linuxppc-dev@...ts.ozlabs.org,
        kvm@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [PATCH] KVM: PPC: Add the missing character/behaviour bits for KVM_PPC_GET_CPU_CHAR ioctl

Add the missing bits for the character and behaviour masks used to
indicate the valid bits in the result of KVM_PPC_GET_CPU_CHAR ioctl
used by KVM guests to know the host mitigation status.

Signed-off-by: Gautam Menghani <gautam@...ux.ibm.com>
---
 arch/powerpc/include/uapi/asm/kvm.h |  6 ++++++
 arch/powerpc/kvm/powerpc.c          | 10 ++++++++--
 2 files changed, 14 insertions(+), 2 deletions(-)

diff --git a/arch/powerpc/include/uapi/asm/kvm.h b/arch/powerpc/include/uapi/asm/kvm.h
index 077c5437f521..19ad60fb9147 100644
--- a/arch/powerpc/include/uapi/asm/kvm.h
+++ b/arch/powerpc/include/uapi/asm/kvm.h
@@ -450,11 +450,17 @@ struct kvm_ppc_cpu_char {
 #define KVM_PPC_CPU_CHAR_MTTRIG_THR_RECONF	(1ULL << 57)
 #define KVM_PPC_CPU_CHAR_COUNT_CACHE_DIS	(1ULL << 56)
 #define KVM_PPC_CPU_CHAR_BCCTR_FLUSH_ASSIST	(1ull << 54)
+#define KVM_PPC_CPU_CHAR_BCCTR_LINK_FLUSH_ASSIST (1ull << 52)
 
 #define KVM_PPC_CPU_BEHAV_FAVOUR_SECURITY	(1ULL << 63)
 #define KVM_PPC_CPU_BEHAV_L1D_FLUSH_PR		(1ULL << 62)
 #define KVM_PPC_CPU_BEHAV_BNDS_CHK_SPEC_BAR	(1ULL << 61)
+#define KVM_PPC_CPU_BEHAV_FAVOUR_SECURITY_H	(1ull << 60)
 #define KVM_PPC_CPU_BEHAV_FLUSH_COUNT_CACHE	(1ull << 58)
+#define KVM_PPC_CPU_BEHAV_FLUSH_LINK_STACK	(1ull << 57)
+#define KVM_PPC_CPU_BEHAV_NO_L1D_FLUSH_ENTRY	(1ull << 56)
+#define KVM_PPC_CPU_BEHAV_NO_L1D_FLUSH_UACCESS (1ull << 55)
+#define KVM_PPC_CPU_BEHAV_NO_STF_BARRIER	(1ull << 54)
 
 /* Per-vcpu XICS interrupt controller state */
 #define KVM_REG_PPC_ICP_STATE	(KVM_REG_PPC | KVM_REG_SIZE_U64 | 0x8c)
diff --git a/arch/powerpc/kvm/powerpc.c b/arch/powerpc/kvm/powerpc.c
index 2ba057171ebe..642740c86272 100644
--- a/arch/powerpc/kvm/powerpc.c
+++ b/arch/powerpc/kvm/powerpc.c
@@ -2261,11 +2261,17 @@ static int pseries_get_cpu_char(struct kvm_ppc_cpu_char *cp)
 			KVM_PPC_CPU_CHAR_BR_HINT_HONOURED |
 			KVM_PPC_CPU_CHAR_MTTRIG_THR_RECONF |
 			KVM_PPC_CPU_CHAR_COUNT_CACHE_DIS |
-			KVM_PPC_CPU_CHAR_BCCTR_FLUSH_ASSIST;
+			KVM_PPC_CPU_CHAR_BCCTR_FLUSH_ASSIST |
+			KVM_PPC_CPU_CHAR_BCCTR_LINK_FLUSH_ASSIST;
 		cp->behaviour_mask = KVM_PPC_CPU_BEHAV_FAVOUR_SECURITY |
 			KVM_PPC_CPU_BEHAV_L1D_FLUSH_PR |
 			KVM_PPC_CPU_BEHAV_BNDS_CHK_SPEC_BAR |
-			KVM_PPC_CPU_BEHAV_FLUSH_COUNT_CACHE;
+			KVM_PPC_CPU_BEHAV_FAVOUR_SECURITY_H |
+			KVM_PPC_CPU_BEHAV_FLUSH_COUNT_CACHE |
+			KVM_PPC_CPU_BEHAV_FLUSH_LINK_STACK |
+			KVM_PPC_CPU_BEHAV_NO_L1D_FLUSH_ENTRY |
+			KVM_PPC_CPU_BEHAV_NO_L1D_FLUSH_UACCESS |
+			KVM_PPC_CPU_BEHAV_NO_STF_BARRIER;
 	}
 	return 0;
 }
-- 
2.50.1 (Apple Git-155)