* [PATCH v2 1/3] KVM: arm64: Define helper for EL2 registers with custom visibility
2024-08-21 23:35 [PATCH v2 0/3] KVM: arm64: Control visibility of S1PIE related sysregs to userspace Mark Brown
@ 2024-08-21 23:35 ` Mark Brown
2024-08-21 23:35 ` [PATCH v2 2/3] KVM: arm64: Hide TCR2_EL1 from userspace when disabled for guests Mark Brown
2024-08-21 23:35 ` [PATCH v2 3/3] KVM: arm64: Hide S1PIE registers " Mark Brown
2 siblings, 0 replies; 5+ messages in thread
From: Mark Brown @ 2024-08-21 23:35 UTC (permalink / raw)
To: Marc Zyngier, Oliver Upton, James Morse, Suzuki K Poulose,
Catalin Marinas, Will Deacon, Joey Gouly
Cc: linux-arm-kernel, kvmarm, linux-kernel, Mark Brown,
20240813144738.2048302-1-maz
In preparation for adding more visibility filtering for EL2 registers add
a helper macro like EL2_REG() which allows specification of a custom
visibility operation.
Signed-off-by: Mark Brown <broonie@kernel.org>
---
arch/arm64/kvm/sys_regs.c | 13 +++++++++++--
1 file changed, 11 insertions(+), 2 deletions(-)
diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
index d0b4509e59cb..1af15140e067 100644
--- a/arch/arm64/kvm/sys_regs.c
+++ b/arch/arm64/kvm/sys_regs.c
@@ -2136,6 +2136,15 @@ static bool bad_redir_trap(struct kvm_vcpu *vcpu,
.val = v, \
}
+#define EL2_REG_FILTERED(name, acc, rst, v, filter) { \
+ SYS_DESC(SYS_##name), \
+ .access = acc, \
+ .reset = rst, \
+ .reg = name, \
+ .visibility = filter, \
+ .val = v, \
+}
+
#define EL2_REG_VNCR(name, rst, v) EL2_REG(name, bad_vncr_trap, rst, v)
#define EL2_REG_REDIR(name, rst, v) EL2_REG(name, bad_redir_trap, rst, v)
@@ -2803,8 +2812,8 @@ static const struct sys_reg_desc sys_reg_descs[] = {
EL2_REG_VNCR(HFGITR_EL2, reset_val, 0),
EL2_REG_VNCR(HACR_EL2, reset_val, 0),
- { SYS_DESC(SYS_ZCR_EL2), .access = access_zcr_el2, .reset = reset_val,
- .visibility = sve_el2_visibility, .reg = ZCR_EL2 },
+ EL2_REG_FILTERED(ZCR_EL2, access_zcr_el2, reset_val, 0,
+ sve_el2_visibility),
EL2_REG_VNCR(HCRX_EL2, reset_val, 0),
--
2.39.2
^ permalink raw reply related [flat|nested] 5+ messages in thread* [PATCH v2 2/3] KVM: arm64: Hide TCR2_EL1 from userspace when disabled for guests
2024-08-21 23:35 [PATCH v2 0/3] KVM: arm64: Control visibility of S1PIE related sysregs to userspace Mark Brown
2024-08-21 23:35 ` [PATCH v2 1/3] KVM: arm64: Define helper for EL2 registers with custom visibility Mark Brown
@ 2024-08-21 23:35 ` Mark Brown
2024-09-02 19:12 ` Marc Zyngier
2024-08-21 23:35 ` [PATCH v2 3/3] KVM: arm64: Hide S1PIE registers " Mark Brown
2 siblings, 1 reply; 5+ messages in thread
From: Mark Brown @ 2024-08-21 23:35 UTC (permalink / raw)
To: Marc Zyngier, Oliver Upton, James Morse, Suzuki K Poulose,
Catalin Marinas, Will Deacon, Joey Gouly
Cc: linux-arm-kernel, kvmarm, linux-kernel, Mark Brown,
20240813144738.2048302-1-maz
When the guest does not support FEAT_TCR2 we should not allow any access
to it in order to ensure that we do not create spurious issues with guest
migration. Add a visibility operation for it.
Fixes: fbff56068232 ("KVM: arm64: Save/restore TCR2_EL1")
Signed-off-by: Mark Brown <broonie@kernel.org>
---
arch/arm64/include/asm/kvm_host.h | 3 +++
arch/arm64/kvm/sys_regs.c | 29 ++++++++++++++++++++++++++---
2 files changed, 29 insertions(+), 3 deletions(-)
diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
index ab4c675b491d..7889e5f4009f 100644
--- a/arch/arm64/include/asm/kvm_host.h
+++ b/arch/arm64/include/asm/kvm_host.h
@@ -1476,4 +1476,7 @@ void kvm_set_vm_id_reg(struct kvm *kvm, u32 reg, u64 val);
(pa + pi + pa3) == 1; \
})
+#define kvm_has_tcr2(k) \
+ (kvm_has_feat((k), ID_AA64MMFR3_EL1, TCRX, IMP))
+
#endif /* __ARM64_KVM_HOST_H__ */
diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
index 1af15140e067..6d5f43781042 100644
--- a/arch/arm64/kvm/sys_regs.c
+++ b/arch/arm64/kvm/sys_regs.c
@@ -2319,6 +2319,27 @@ static bool access_zcr_el2(struct kvm_vcpu *vcpu,
return true;
}
+static unsigned int tcr2_visibility(const struct kvm_vcpu *vcpu,
+ const struct sys_reg_desc *rd)
+{
+ if (kvm_has_tcr2(vcpu->kvm))
+ return 0;
+
+ return REG_HIDDEN;
+}
+
+static unsigned int tcr2_el2_visibility(const struct kvm_vcpu *vcpu,
+ const struct sys_reg_desc *rd)
+{
+ unsigned int r;
+
+ r = el2_visibility(vcpu, rd);
+ if (r)
+ return r;
+
+ return tcr2_visibility(vcpu, rd);
+}
+
/*
* Architected system registers.
* Important: Must be sorted ascending by Op0, Op1, CRn, CRm, Op2
@@ -2503,7 +2524,8 @@ static const struct sys_reg_desc sys_reg_descs[] = {
{ SYS_DESC(SYS_TTBR0_EL1), access_vm_reg, reset_unknown, TTBR0_EL1 },
{ SYS_DESC(SYS_TTBR1_EL1), access_vm_reg, reset_unknown, TTBR1_EL1 },
{ SYS_DESC(SYS_TCR_EL1), access_vm_reg, reset_val, TCR_EL1, 0 },
- { SYS_DESC(SYS_TCR2_EL1), access_vm_reg, reset_val, TCR2_EL1, 0 },
+ { SYS_DESC(SYS_TCR2_EL1), access_vm_reg, reset_val, TCR2_EL1, 0,
+ .visibility = tcr2_visibility },
PTRAUTH_KEY(APIA),
PTRAUTH_KEY(APIB),
@@ -2820,7 +2842,8 @@ static const struct sys_reg_desc sys_reg_descs[] = {
EL2_REG(TTBR0_EL2, access_rw, reset_val, 0),
EL2_REG(TTBR1_EL2, access_rw, reset_val, 0),
EL2_REG(TCR_EL2, access_rw, reset_val, TCR_EL2_RES1),
- EL2_REG(TCR2_EL2, access_tcr2_el2, reset_val, TCR2_EL2_RES1),
+ EL2_REG_FILTERED(TCR2_EL2, access_tcr2_el2, reset_val, TCR2_EL2_RES1,
+ tcr2_el2_visibility),
EL2_REG_VNCR(VTTBR_EL2, reset_val, 0),
EL2_REG_VNCR(VTCR_EL2, reset_val, 0),
@@ -4626,7 +4649,7 @@ void kvm_calculate_traps(struct kvm_vcpu *vcpu)
if (kvm_has_feat(kvm, ID_AA64ISAR2_EL1, MOPS, IMP))
vcpu->arch.hcrx_el2 |= (HCRX_EL2_MSCEn | HCRX_EL2_MCE2);
- if (kvm_has_feat(kvm, ID_AA64MMFR3_EL1, TCRX, IMP))
+ if (kvm_has_tcr2(kvm))
vcpu->arch.hcrx_el2 |= HCRX_EL2_TCR2En;
}
--
2.39.2
^ permalink raw reply related [flat|nested] 5+ messages in thread* Re: [PATCH v2 2/3] KVM: arm64: Hide TCR2_EL1 from userspace when disabled for guests
2024-08-21 23:35 ` [PATCH v2 2/3] KVM: arm64: Hide TCR2_EL1 from userspace when disabled for guests Mark Brown
@ 2024-09-02 19:12 ` Marc Zyngier
0 siblings, 0 replies; 5+ messages in thread
From: Marc Zyngier @ 2024-09-02 19:12 UTC (permalink / raw)
To: Mark Brown
Cc: Oliver Upton, James Morse, Suzuki K Poulose, Catalin Marinas,
Will Deacon, Joey Gouly, linux-arm-kernel, kvmarm, linux-kernel,
20240813144738.2048302-1-maz
On Thu, 22 Aug 2024 00:35:37 +0100,
Mark Brown <broonie@kernel.org> wrote:
>
> When the guest does not support FEAT_TCR2 we should not allow any access
> to it in order to ensure that we do not create spurious issues with guest
> migration. Add a visibility operation for it.
>
> Fixes: fbff56068232 ("KVM: arm64: Save/restore TCR2_EL1")
> Signed-off-by: Mark Brown <broonie@kernel.org>
> ---
> arch/arm64/include/asm/kvm_host.h | 3 +++
> arch/arm64/kvm/sys_regs.c | 29 ++++++++++++++++++++++++++---
> 2 files changed, 29 insertions(+), 3 deletions(-)
>
> diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
> index ab4c675b491d..7889e5f4009f 100644
> --- a/arch/arm64/include/asm/kvm_host.h
> +++ b/arch/arm64/include/asm/kvm_host.h
> @@ -1476,4 +1476,7 @@ void kvm_set_vm_id_reg(struct kvm *kvm, u32 reg, u64 val);
> (pa + pi + pa3) == 1; \
> })
>
> +#define kvm_has_tcr2(k) \
> + (kvm_has_feat((k), ID_AA64MMFR3_EL1, TCRX, IMP))
> +
> #endif /* __ARM64_KVM_HOST_H__ */
> diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
> index 1af15140e067..6d5f43781042 100644
> --- a/arch/arm64/kvm/sys_regs.c
> +++ b/arch/arm64/kvm/sys_regs.c
> @@ -2319,6 +2319,27 @@ static bool access_zcr_el2(struct kvm_vcpu *vcpu,
> return true;
> }
>
> +static unsigned int tcr2_visibility(const struct kvm_vcpu *vcpu,
> + const struct sys_reg_desc *rd)
> +{
> + if (kvm_has_tcr2(vcpu->kvm))
> + return 0;
> +
> + return REG_HIDDEN;
> +}
> +
> +static unsigned int tcr2_el2_visibility(const struct kvm_vcpu *vcpu,
> + const struct sys_reg_desc *rd)
> +{
> + unsigned int r;
> +
> + r = el2_visibility(vcpu, rd);
> + if (r)
> + return r;
> +
> + return tcr2_visibility(vcpu, rd);
> +}
> +
> /*
> * Architected system registers.
> * Important: Must be sorted ascending by Op0, Op1, CRn, CRm, Op2
> @@ -2503,7 +2524,8 @@ static const struct sys_reg_desc sys_reg_descs[] = {
> { SYS_DESC(SYS_TTBR0_EL1), access_vm_reg, reset_unknown, TTBR0_EL1 },
> { SYS_DESC(SYS_TTBR1_EL1), access_vm_reg, reset_unknown, TTBR1_EL1 },
> { SYS_DESC(SYS_TCR_EL1), access_vm_reg, reset_val, TCR_EL1, 0 },
> - { SYS_DESC(SYS_TCR2_EL1), access_vm_reg, reset_val, TCR2_EL1, 0 },
> + { SYS_DESC(SYS_TCR2_EL1), access_vm_reg, reset_val, TCR2_EL1, 0,
> + .visibility = tcr2_visibility },
With this, we should be able to simplify the accessor, shouldn't we?
>
> PTRAUTH_KEY(APIA),
> PTRAUTH_KEY(APIB),
> @@ -2820,7 +2842,8 @@ static const struct sys_reg_desc sys_reg_descs[] = {
> EL2_REG(TTBR0_EL2, access_rw, reset_val, 0),
> EL2_REG(TTBR1_EL2, access_rw, reset_val, 0),
> EL2_REG(TCR_EL2, access_rw, reset_val, TCR_EL2_RES1),
> - EL2_REG(TCR2_EL2, access_tcr2_el2, reset_val, TCR2_EL2_RES1),
> + EL2_REG_FILTERED(TCR2_EL2, access_tcr2_el2, reset_val, TCR2_EL2_RES1,
> + tcr2_el2_visibility),
Same thing here.
Thanks,
M.
--
Without deviation from the norm, progress is not possible.
^ permalink raw reply [flat|nested] 5+ messages in thread
* [PATCH v2 3/3] KVM: arm64: Hide S1PIE registers from userspace when disabled for guests
2024-08-21 23:35 [PATCH v2 0/3] KVM: arm64: Control visibility of S1PIE related sysregs to userspace Mark Brown
2024-08-21 23:35 ` [PATCH v2 1/3] KVM: arm64: Define helper for EL2 registers with custom visibility Mark Brown
2024-08-21 23:35 ` [PATCH v2 2/3] KVM: arm64: Hide TCR2_EL1 from userspace when disabled for guests Mark Brown
@ 2024-08-21 23:35 ` Mark Brown
2 siblings, 0 replies; 5+ messages in thread
From: Mark Brown @ 2024-08-21 23:35 UTC (permalink / raw)
To: Marc Zyngier, Oliver Upton, James Morse, Suzuki K Poulose,
Catalin Marinas, Will Deacon, Joey Gouly
Cc: linux-arm-kernel, kvmarm, linux-kernel, Mark Brown,
20240813144738.2048302-1-maz
When the guest does not support S1PIE we should not allow any access
to the system registers it adds in order to ensure that we do not create
spurious issues with guest migration. Add a visibility operation for these
registers.
Fixes: 86f9de9db178 ("KVM: arm64: Save/restore PIE registers")
Signed-off-by: Mark Brown <broonie@kernel.org>
---
arch/arm64/include/asm/kvm_host.h | 3 +++
arch/arm64/kvm/sys_regs.c | 35 ++++++++++++++++++++++++++++++-----
2 files changed, 33 insertions(+), 5 deletions(-)
diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
index 7889e5f4009f..fd161d41df52 100644
--- a/arch/arm64/include/asm/kvm_host.h
+++ b/arch/arm64/include/asm/kvm_host.h
@@ -1479,4 +1479,7 @@ void kvm_set_vm_id_reg(struct kvm *kvm, u32 reg, u64 val);
#define kvm_has_tcr2(k) \
(kvm_has_feat((k), ID_AA64MMFR3_EL1, TCRX, IMP))
+#define kvm_has_s1pie(k) \
+ (kvm_has_feat((k), ID_AA64MMFR3_EL1, S1PIE, IMP))
+
#endif /* __ARM64_KVM_HOST_H__ */
diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
index 6d5f43781042..3824f6d13bf6 100644
--- a/arch/arm64/kvm/sys_regs.c
+++ b/arch/arm64/kvm/sys_regs.c
@@ -2340,6 +2340,27 @@ static unsigned int tcr2_el2_visibility(const struct kvm_vcpu *vcpu,
return tcr2_visibility(vcpu, rd);
}
+static unsigned int s1pie_visibility(const struct kvm_vcpu *vcpu,
+ const struct sys_reg_desc *rd)
+{
+ if (kvm_has_s1pie(vcpu->kvm))
+ return 0;
+
+ return REG_HIDDEN;
+}
+
+static unsigned int s1pie_el2_visibility(const struct kvm_vcpu *vcpu,
+ const struct sys_reg_desc *rd)
+{
+ unsigned int r;
+
+ r = el2_visibility(vcpu, rd);
+ if (r)
+ return r;
+
+ return s1pie_visibility(vcpu, rd);
+}
+
/*
* Architected system registers.
* Important: Must be sorted ascending by Op0, Op1, CRn, CRm, Op2
@@ -2577,8 +2598,10 @@ static const struct sys_reg_desc sys_reg_descs[] = {
{ SYS_DESC(SYS_PMMIR_EL1), trap_raz_wi },
{ SYS_DESC(SYS_MAIR_EL1), access_vm_reg, reset_unknown, MAIR_EL1 },
- { SYS_DESC(SYS_PIRE0_EL1), NULL, reset_unknown, PIRE0_EL1 },
- { SYS_DESC(SYS_PIR_EL1), NULL, reset_unknown, PIR_EL1 },
+ { SYS_DESC(SYS_PIRE0_EL1), NULL, reset_unknown, PIRE0_EL1,
+ .visibility = s1pie_visibility },
+ { SYS_DESC(SYS_PIR_EL1), NULL, reset_unknown, PIR_EL1,
+ .visibility = s1pie_visibility },
{ SYS_DESC(SYS_AMAIR_EL1), access_vm_reg, reset_amair_el1, AMAIR_EL1 },
{ SYS_DESC(SYS_LORSA_EL1), trap_loregion },
@@ -2875,8 +2898,10 @@ static const struct sys_reg_desc sys_reg_descs[] = {
EL2_REG(HPFAR_EL2, access_rw, reset_val, 0),
EL2_REG(MAIR_EL2, access_rw, reset_val, 0),
- EL2_REG(PIRE0_EL2, check_s1pie_access_rw, reset_val, 0),
- EL2_REG(PIR_EL2, check_s1pie_access_rw, reset_val, 0),
+ EL2_REG_FILTERED(PIRE0_EL2, check_s1pie_access_rw, reset_val, 0,
+ s1pie_el2_visibility),
+ EL2_REG_FILTERED(PIR_EL2, check_s1pie_access_rw, reset_val, 0,
+ s1pie_el2_visibility),
EL2_REG(AMAIR_EL2, access_rw, reset_val, 0),
EL2_REG(VBAR_EL2, access_rw, reset_val, 0),
@@ -4691,7 +4716,7 @@ void kvm_calculate_traps(struct kvm_vcpu *vcpu)
HFGITR_EL2_TLBIRVAAE1OS |
HFGITR_EL2_TLBIRVAE1OS);
- if (!kvm_has_feat(kvm, ID_AA64MMFR3_EL1, S1PIE, IMP))
+ if (!kvm_has_s1pie(kvm))
kvm->arch.fgu[HFGxTR_GROUP] |= (HFGxTR_EL2_nPIRE0_EL1 |
HFGxTR_EL2_nPIR_EL1);
--
2.39.2
^ permalink raw reply related [flat|nested] 5+ messages in thread