[PATCH 0/2] KVM: arm64: Handle MTE Set/Way CMOs

[PATCH 0/2] KVM: arm64: Handle MTE Set/Way CMOs

[Marc Zyngier]

When the MTE support was added, it seens the handling of MTE Set/Way
was ommited, meaning that the guest will get an UNDEF if it tries to
do something that is quite stupid, but still allowed by the
architecture...

Found by inspection while writting the trap support for NV.

Marc Zyngier (2):
  arm64: Add missing Set/Way CMO encodings
  KVM: arm64: Handle trap of tagged Set/Way CMOs

 arch/arm64/include/asm/sysreg.h |  6 ++++++
 arch/arm64/kvm/sys_regs.c       | 19 +++++++++++++++++++
 2 files changed, 25 insertions(+)

-- 
2.34.1

[PATCH 0/2] KVM: arm64: Handle MTE Set/Way CMOs

[Marc Zyngier]

When the MTE support was added, it seens the handling of MTE Set/Way
was ommited, meaning that the guest will get an UNDEF if it tries to
do something that is quite stupid, but still allowed by the
architecture...

Found by inspection while writting the trap support for NV.

Marc Zyngier (2):
  arm64: Add missing Set/Way CMO encodings
  KVM: arm64: Handle trap of tagged Set/Way CMOs

 arch/arm64/include/asm/sysreg.h |  6 ++++++
 arch/arm64/kvm/sys_regs.c       | 19 +++++++++++++++++++
 2 files changed, 25 insertions(+)

-- 
2.34.1


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[PATCH 1/2] arm64: Add missing Set/Way CMO encodings

[Marc Zyngier]

Add the missing Set/Way CMOs that apply to tagged memory.

Signed-off-by: Marc Zyngier <maz@kernel.org>
---
 arch/arm64/include/asm/sysreg.h | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/arch/arm64/include/asm/sysreg.h b/arch/arm64/include/asm/sysreg.h
index e72d9aaab6b1..eefd712f2430 100644
--- a/arch/arm64/include/asm/sysreg.h
+++ b/arch/arm64/include/asm/sysreg.h
@@ -115,8 +115,14 @@
 #define SB_BARRIER_INSN			__SYS_BARRIER_INSN(0, 7, 31)
 
 #define SYS_DC_ISW			sys_insn(1, 0, 7, 6, 2)
+#define SYS_DC_IGSW			sys_insn(1, 0, 7, 6, 4)
+#define SYS_DC_IGDSW			sys_insn(1, 0, 7, 6, 6)
 #define SYS_DC_CSW			sys_insn(1, 0, 7, 10, 2)
+#define SYS_DC_CGSW			sys_insn(1, 0, 7, 10, 4)
+#define SYS_DC_CGDSW			sys_insn(1, 0, 7, 10, 6)
 #define SYS_DC_CISW			sys_insn(1, 0, 7, 14, 2)
+#define SYS_DC_CIGSW			sys_insn(1, 0, 7, 14, 4)
+#define SYS_DC_CIGDSW			sys_insn(1, 0, 7, 14, 6)
 
 /*
  * Automatically generated definitions for system registers, the
-- 
2.34.1

[PATCH 1/2] arm64: Add missing Set/Way CMO encodings

[Marc Zyngier]

Add the missing Set/Way CMOs that apply to tagged memory.

Signed-off-by: Marc Zyngier <maz@kernel.org>
---
 arch/arm64/include/asm/sysreg.h | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/arch/arm64/include/asm/sysreg.h b/arch/arm64/include/asm/sysreg.h
index e72d9aaab6b1..eefd712f2430 100644
--- a/arch/arm64/include/asm/sysreg.h
+++ b/arch/arm64/include/asm/sysreg.h
@@ -115,8 +115,14 @@
 #define SB_BARRIER_INSN			__SYS_BARRIER_INSN(0, 7, 31)
 
 #define SYS_DC_ISW			sys_insn(1, 0, 7, 6, 2)
+#define SYS_DC_IGSW			sys_insn(1, 0, 7, 6, 4)
+#define SYS_DC_IGDSW			sys_insn(1, 0, 7, 6, 6)
 #define SYS_DC_CSW			sys_insn(1, 0, 7, 10, 2)
+#define SYS_DC_CGSW			sys_insn(1, 0, 7, 10, 4)
+#define SYS_DC_CGDSW			sys_insn(1, 0, 7, 10, 6)
 #define SYS_DC_CISW			sys_insn(1, 0, 7, 14, 2)
+#define SYS_DC_CIGSW			sys_insn(1, 0, 7, 14, 4)
+#define SYS_DC_CIGDSW			sys_insn(1, 0, 7, 14, 6)
 
 /*
  * Automatically generated definitions for system registers, the
-- 
2.34.1


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[PATCH 2/2] KVM: arm64: Handle trap of tagged Set/Way CMOs

[Marc Zyngier]

We appear to have missed the Set/Way CMOs when adding MTE support.
Not that we really expect anyone to use them, but you never know
what stupidity some people can come up with...

Treat these mostly like we deal with the classic S/W CMOs, only
with an additional check that MTE really is enabled.

Signed-off-by: Marc Zyngier <maz@kernel.org>
---
 arch/arm64/kvm/sys_regs.c | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)

diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
index 71b12094d613..753aa7418149 100644
--- a/arch/arm64/kvm/sys_regs.c
+++ b/arch/arm64/kvm/sys_regs.c
@@ -211,6 +211,19 @@ static bool access_dcsw(struct kvm_vcpu *vcpu,
 	return true;
 }
 
+static bool access_dcgsw(struct kvm_vcpu *vcpu,
+			 struct sys_reg_params *p,
+			 const struct sys_reg_desc *r)
+{
+	if (!kvm_has_mte(vcpu->kvm)) {
+		kvm_inject_undefined(vcpu);
+		return false;
+	}
+
+	/* Treat MTE S/W ops as we treat the classic ones: with contempt */
+	return access_dcsw(vcpu, p, r);
+}
+
 static void get_access_mask(const struct sys_reg_desc *r, u64 *mask, u64 *shift)
 {
 	switch (r->aarch32_map) {
@@ -1756,8 +1769,14 @@ static bool access_spsr(struct kvm_vcpu *vcpu,
  */
 static const struct sys_reg_desc sys_reg_descs[] = {
 	{ SYS_DESC(SYS_DC_ISW), access_dcsw },
+	{ SYS_DESC(SYS_DC_IGSW), access_dcgsw },
+	{ SYS_DESC(SYS_DC_IGDSW), access_dcgsw },
 	{ SYS_DESC(SYS_DC_CSW), access_dcsw },
+	{ SYS_DESC(SYS_DC_CGSW), access_dcgsw },
+	{ SYS_DESC(SYS_DC_CGDSW), access_dcgsw },
 	{ SYS_DESC(SYS_DC_CISW), access_dcsw },
+	{ SYS_DESC(SYS_DC_CIGSW), access_dcgsw },
+	{ SYS_DESC(SYS_DC_CIGDSW), access_dcgsw },
 
 	DBG_BCR_BVR_WCR_WVR_EL1(0),
 	DBG_BCR_BVR_WCR_WVR_EL1(1),
-- 
2.34.1

[PATCH 2/2] KVM: arm64: Handle trap of tagged Set/Way CMOs

[Marc Zyngier]

We appear to have missed the Set/Way CMOs when adding MTE support.
Not that we really expect anyone to use them, but you never know
what stupidity some people can come up with...

Treat these mostly like we deal with the classic S/W CMOs, only
with an additional check that MTE really is enabled.

Signed-off-by: Marc Zyngier <maz@kernel.org>
---
 arch/arm64/kvm/sys_regs.c | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)

diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
index 71b12094d613..753aa7418149 100644
--- a/arch/arm64/kvm/sys_regs.c
+++ b/arch/arm64/kvm/sys_regs.c
@@ -211,6 +211,19 @@ static bool access_dcsw(struct kvm_vcpu *vcpu,
 	return true;
 }
 
+static bool access_dcgsw(struct kvm_vcpu *vcpu,
+			 struct sys_reg_params *p,
+			 const struct sys_reg_desc *r)
+{
+	if (!kvm_has_mte(vcpu->kvm)) {
+		kvm_inject_undefined(vcpu);
+		return false;
+	}
+
+	/* Treat MTE S/W ops as we treat the classic ones: with contempt */
+	return access_dcsw(vcpu, p, r);
+}
+
 static void get_access_mask(const struct sys_reg_desc *r, u64 *mask, u64 *shift)
 {
 	switch (r->aarch32_map) {
@@ -1756,8 +1769,14 @@ static bool access_spsr(struct kvm_vcpu *vcpu,
  */
 static const struct sys_reg_desc sys_reg_descs[] = {
 	{ SYS_DESC(SYS_DC_ISW), access_dcsw },
+	{ SYS_DESC(SYS_DC_IGSW), access_dcgsw },
+	{ SYS_DESC(SYS_DC_IGDSW), access_dcgsw },
 	{ SYS_DESC(SYS_DC_CSW), access_dcsw },
+	{ SYS_DESC(SYS_DC_CGSW), access_dcgsw },
+	{ SYS_DESC(SYS_DC_CGDSW), access_dcgsw },
 	{ SYS_DESC(SYS_DC_CISW), access_dcsw },
+	{ SYS_DESC(SYS_DC_CIGSW), access_dcgsw },
+	{ SYS_DESC(SYS_DC_CIGDSW), access_dcgsw },
 
 	DBG_BCR_BVR_WCR_WVR_EL1(0),
 	DBG_BCR_BVR_WCR_WVR_EL1(1),
-- 
2.34.1


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Re: [PATCH 0/2] KVM: arm64: Handle MTE Set/Way CMOs

[Steven Price]

On 15/05/2023 21:45, Marc Zyngier wrote:
> When the MTE support was added, it seens the handling of MTE Set/Way
> was ommited, meaning that the guest will get an UNDEF if it tries to
> do something that is quite stupid, but still allowed by the
> architecture...

Sorry about that, as you say it's quite a stupid thing for a guest to
attempt and it hadn't occurred to me when implementing KVM support.

Both patches:

Reviewed-by: Steven Price <steven.price@arm.com>

Thanks,

Steve

> 
> Found by inspection while writting the trap support for NV.
> 
> Marc Zyngier (2):
>   arm64: Add missing Set/Way CMO encodings
>   KVM: arm64: Handle trap of tagged Set/Way CMOs
> 
>  arch/arm64/include/asm/sysreg.h |  6 ++++++
>  arch/arm64/kvm/sys_regs.c       | 19 +++++++++++++++++++
>  2 files changed, 25 insertions(+)
> 

Re: [PATCH 0/2] KVM: arm64: Handle MTE Set/Way CMOs

[Steven Price]

On 15/05/2023 21:45, Marc Zyngier wrote:
> When the MTE support was added, it seens the handling of MTE Set/Way
> was ommited, meaning that the guest will get an UNDEF if it tries to
> do something that is quite stupid, but still allowed by the
> architecture...

Sorry about that, as you say it's quite a stupid thing for a guest to
attempt and it hadn't occurred to me when implementing KVM support.

Both patches:

Reviewed-by: Steven Price <steven.price@arm.com>

Thanks,

Steve

> 
> Found by inspection while writting the trap support for NV.
> 
> Marc Zyngier (2):
>   arm64: Add missing Set/Way CMO encodings
>   KVM: arm64: Handle trap of tagged Set/Way CMOs
> 
>  arch/arm64/include/asm/sysreg.h |  6 ++++++
>  arch/arm64/kvm/sys_regs.c       | 19 +++++++++++++++++++
>  2 files changed, 25 insertions(+)
> 


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Re: [PATCH 1/2] arm64: Add missing Set/Way CMO encodings

[Cornelia Huck]

On Mon, May 15 2023, Marc Zyngier <maz@kernel.org> wrote:

> Add the missing Set/Way CMOs that apply to tagged memory.
>
> Signed-off-by: Marc Zyngier <maz@kernel.org>
> ---
>  arch/arm64/include/asm/sysreg.h | 6 ++++++
>  1 file changed, 6 insertions(+)

Reviewed-by: Cornelia Huck <cohuck@redhat.com>

Re: [PATCH 1/2] arm64: Add missing Set/Way CMO encodings

[Cornelia Huck]

On Mon, May 15 2023, Marc Zyngier <maz@kernel.org> wrote:

> Add the missing Set/Way CMOs that apply to tagged memory.
>
> Signed-off-by: Marc Zyngier <maz@kernel.org>
> ---
>  arch/arm64/include/asm/sysreg.h | 6 ++++++
>  1 file changed, 6 insertions(+)

Reviewed-by: Cornelia Huck <cohuck@redhat.com>


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Re: [PATCH 2/2] KVM: arm64: Handle trap of tagged Set/Way CMOs

[Cornelia Huck]

On Mon, May 15 2023, Marc Zyngier <maz@kernel.org> wrote:

> We appear to have missed the Set/Way CMOs when adding MTE support.
> Not that we really expect anyone to use them, but you never know
> what stupidity some people can come up with...
>
> Treat these mostly like we deal with the classic S/W CMOs, only
> with an additional check that MTE really is enabled.
>
> Signed-off-by: Marc Zyngier <maz@kernel.org>
> ---
>  arch/arm64/kvm/sys_regs.c | 19 +++++++++++++++++++
>  1 file changed, 19 insertions(+)

Reviewed-by: Cornelia Huck <cohuck@redhat.com>

Re: [PATCH 2/2] KVM: arm64: Handle trap of tagged Set/Way CMOs

[Cornelia Huck]

On Mon, May 15 2023, Marc Zyngier <maz@kernel.org> wrote:

> We appear to have missed the Set/Way CMOs when adding MTE support.
> Not that we really expect anyone to use them, but you never know
> what stupidity some people can come up with...
>
> Treat these mostly like we deal with the classic S/W CMOs, only
> with an additional check that MTE really is enabled.
>
> Signed-off-by: Marc Zyngier <maz@kernel.org>
> ---
>  arch/arm64/kvm/sys_regs.c | 19 +++++++++++++++++++
>  1 file changed, 19 insertions(+)

Reviewed-by: Cornelia Huck <cohuck@redhat.com>


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Re: [PATCH 0/2] KVM: arm64: Handle MTE Set/Way CMOs

[Oliver Upton]

On Mon, May 15, 2023 at 09:45:59PM +0100, Marc Zyngier wrote:
> When the MTE support was added, it seens the handling of MTE Set/Way
> was ommited, meaning that the guest will get an UNDEF if it tries to
> do something that is quite stupid, but still allowed by the
> architecture...
> 
> Found by inspection while writting the trap support for NV.
> 
> Marc Zyngier (2):
>   arm64: Add missing Set/Way CMO encodings
>   KVM: arm64: Handle trap of tagged Set/Way CMOs

For the series:

Reviewed-by: Oliver Upton <oliver.upton@linux.dev>

-- 
Thanks,
Oliver

Re: [PATCH 0/2] KVM: arm64: Handle MTE Set/Way CMOs

[Oliver Upton]

On Mon, May 15, 2023 at 09:45:59PM +0100, Marc Zyngier wrote:
> When the MTE support was added, it seens the handling of MTE Set/Way
> was ommited, meaning that the guest will get an UNDEF if it tries to
> do something that is quite stupid, but still allowed by the
> architecture...
> 
> Found by inspection while writting the trap support for NV.
> 
> Marc Zyngier (2):
>   arm64: Add missing Set/Way CMO encodings
>   KVM: arm64: Handle trap of tagged Set/Way CMOs

For the series:

Reviewed-by: Oliver Upton <oliver.upton@linux.dev>

-- 
Thanks,
Oliver

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Re: [PATCH 0/2] KVM: arm64: Handle MTE Set/Way CMOs

[Marc Zyngier]

On Mon, 15 May 2023 21:45:59 +0100, Marc Zyngier wrote:
> When the MTE support was added, it seens the handling of MTE Set/Way
> was ommited, meaning that the guest will get an UNDEF if it tries to
> do something that is quite stupid, but still allowed by the
> architecture...
> 
> Found by inspection while writting the trap support for NV.
> 
> [...]

Applied to fixes, thanks!

[1/2] arm64: Add missing Set/Way CMO encodings
      commit: 8d0f019e4c4f2ee2de81efd9bf1c27e9fb3c0460
[2/2] KVM: arm64: Handle trap of tagged Set/Way CMOs
      commit: d282fa3c5ccb7a0029c418f358143689553b6447

Cheers,

	M.
-- 
Without deviation from the norm, progress is not possible.

Re: [PATCH 0/2] KVM: arm64: Handle MTE Set/Way CMOs

[Marc Zyngier]

On Mon, 15 May 2023 21:45:59 +0100, Marc Zyngier wrote:
> When the MTE support was added, it seens the handling of MTE Set/Way
> was ommited, meaning that the guest will get an UNDEF if it tries to
> do something that is quite stupid, but still allowed by the
> architecture...
> 
> Found by inspection while writting the trap support for NV.
> 
> [...]

Applied to fixes, thanks!

[1/2] arm64: Add missing Set/Way CMO encodings
      commit: 8d0f019e4c4f2ee2de81efd9bf1c27e9fb3c0460
[2/2] KVM: arm64: Handle trap of tagged Set/Way CMOs
      commit: d282fa3c5ccb7a0029c418f358143689553b6447

Cheers,

	M.
-- 
Without deviation from the norm, progress is not possible.



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