From: Oliver Upton <oliver.upton@linux.dev>
To: Marc Zyngier <maz@kernel.org>, James Morse <james.morse@arm.com>,
Alexandru Elisei <alexandru.elisei@arm.com>,
Suzuki K Poulose <suzuki.poulose@arm.com>,
Oliver Upton <oliver.upton@linux.dev>,
Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will@kernel.org>
Cc: linux-arm-kernel@lists.infradead.org,
kvmarm@lists.cs.columbia.edu, kvm@vger.kernel.org,
Reiji Watanabe <reijiw@google.com>,
linux-kernel@vger.kernel.org
Subject: [PATCH v2 5/7] KVM: arm64: Add a visibility bit to ignore user writes
Date: Fri, 2 Sep 2022 15:48:01 +0000 [thread overview]
Message-ID: <20220902154804.1939819-6-oliver.upton@linux.dev> (raw)
In-Reply-To: <20220902154804.1939819-1-oliver.upton@linux.dev>
We're about to ignore writes to AArch32 ID registers on AArch64-only
systems. Add a bit to indicate a register is handled as write ignore
when accessed from userspace.
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
---
arch/arm64/kvm/sys_regs.c | 3 +++
arch/arm64/kvm/sys_regs.h | 7 +++++++
2 files changed, 10 insertions(+)
diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
index 0e20a311ea20..6d0511247df4 100644
--- a/arch/arm64/kvm/sys_regs.c
+++ b/arch/arm64/kvm/sys_regs.c
@@ -2775,6 +2775,9 @@ int kvm_sys_reg_set_user(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg,
if (!r)
return -ENOENT;
+ if (sysreg_user_write_ignore(vcpu, r))
+ return 0;
+
if (r->set_user) {
ret = (r->set_user)(vcpu, r, val);
} else {
diff --git a/arch/arm64/kvm/sys_regs.h b/arch/arm64/kvm/sys_regs.h
index e78b51059622..e4ebb3a379fd 100644
--- a/arch/arm64/kvm/sys_regs.h
+++ b/arch/arm64/kvm/sys_regs.h
@@ -86,6 +86,7 @@ struct sys_reg_desc {
#define REG_HIDDEN (1 << 0) /* hidden from userspace and guest */
#define REG_RAZ (1 << 1) /* RAZ from userspace and guest */
+#define REG_USER_WI (1 << 2) /* WI from userspace only */
static __printf(2, 3)
inline void print_sys_reg_msg(const struct sys_reg_params *p,
@@ -157,6 +158,12 @@ static inline bool sysreg_visible_as_raz(const struct kvm_vcpu *vcpu,
return sysreg_visibility(vcpu, r) & REG_RAZ;
}
+static inline bool sysreg_user_write_ignore(const struct kvm_vcpu *vcpu,
+ const struct sys_reg_desc *r)
+{
+ return sysreg_visibility(vcpu, r) & REG_USER_WI;
+}
+
static inline int cmp_sys_reg(const struct sys_reg_desc *i1,
const struct sys_reg_desc *i2)
{
--
2.37.2.789.g6183377224-goog
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next prev parent reply other threads:[~2022-09-02 15:50 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-09-02 15:47 [PATCH v2 0/7] KVM: arm64: Use visibility hook to treat ID regs as RAZ Oliver Upton
2022-09-02 15:47 ` [PATCH v2 1/7] " Oliver Upton
2022-09-02 15:47 ` [PATCH v2 2/7] KVM: arm64: Remove internal accessor helpers for id regs Oliver Upton
2022-09-07 2:00 ` Reiji Watanabe
2022-09-02 15:47 ` [PATCH v2 3/7] KVM: arm64: Drop raz parameter from read_id_reg() Oliver Upton
2022-09-07 2:26 ` Reiji Watanabe
2022-09-02 15:48 ` [PATCH v2 4/7] KVM: arm64: Spin off helper for calling visibility hook Oliver Upton
2022-09-02 15:48 ` Oliver Upton [this message]
2022-09-07 2:40 ` [PATCH v2 5/7] KVM: arm64: Add a visibility bit to ignore user writes Reiji Watanabe
2022-09-02 15:48 ` [PATCH v2 6/7] KVM: arm64: Treat 32bit ID registers as RAZ/WI on 64bit-only system Oliver Upton
2022-09-07 4:52 ` Reiji Watanabe
2022-09-09 10:15 ` Oliver Upton
2022-09-02 15:48 ` [PATCH v2 7/7] KVM: selftests: Add test for RAZ/WI AArch32 ID registers Oliver Upton
2022-09-05 7:31 ` Andrew Jones
2022-09-06 4:54 ` Oliver Upton
2022-09-02 15:52 ` [PATCH v2 0/7] KVM: arm64: Use visibility hook to treat ID regs as RAZ Oliver Upton
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