Re: [PATCH v7 1/3] arm64: kvm: Save/restore MTE registers
On 2021-02-04 14:33, Steven Price wrote:
On 02/02/2021 15:36, Marc Zyngier wrote:
On 2021-01-15 15:28, Steven Price wrote:
Define the new system registers that MTE introduces and context
switch
them. The MTE feature is still hidden from the ID register as it
isn't
supported in a VM yet.
Signed-off-by: Steven Price
---
arch/arm64/include/asm/kvm_host.h | 4 ++
arch/arm64/include/asm/kvm_mte.h | 74
++
arch/arm64/include/asm/sysreg.h | 3 +-
arch/arm64/kernel/asm-offsets.c | 3 +
arch/arm64/kvm/hyp/entry.S | 7 ++
arch/arm64/kvm/hyp/include/hyp/sysreg-sr.h | 4 ++
arch/arm64/kvm/sys_regs.c | 14 ++--
7 files changed, 104 insertions(+), 5 deletions(-)
create mode 100644 arch/arm64/include/asm/kvm_mte.h
diff --git a/arch/arm64/include/asm/kvm_host.h
b/arch/arm64/include/asm/kvm_host.h
index 11beda85ee7e..51590a397e4b 100644
--- a/arch/arm64/include/asm/kvm_host.h
+++ b/arch/arm64/include/asm/kvm_host.h
@@ -148,6 +148,8 @@ enum vcpu_sysreg {
SCTLR_EL1, /* System Control Register */
ACTLR_EL1, /* Auxiliary Control Register */
CPACR_EL1, /* Coprocessor Access Control */
+ RGSR_EL1, /* Random Allocation Tag Seed Register */
+ GCR_EL1, /* Tag Control Register */
ZCR_EL1, /* SVE Control */
TTBR0_EL1, /* Translation Table Base Register 0 */
TTBR1_EL1, /* Translation Table Base Register 1 */
@@ -164,6 +166,8 @@ enum vcpu_sysreg {
TPIDR_EL1, /* Thread ID, Privileged */
AMAIR_EL1, /* Aux Memory Attribute Indirection Register */
CNTKCTL_EL1, /* Timer Control Register (EL1) */
+ TFSRE0_EL1, /* Tag Fault Status Register (EL0) */
+ TFSR_EL1, /* Tag Fault Stauts Register (EL1) */
s/Stauts/Status/
Is there any reason why the MTE registers aren't grouped together?
I has been under the impression this list is sorted by the encoding of
the system registers, although double checking I've screwed up the
order of TFSRE0_EL1/TFSR_EL1, and not all the other fields are sorted
that way.
It grew organically, and was initially matching the original order
of the save/restore sequence. This order has long disappeared with
VHE, and this is essentially nothing more than a bag of indices
(although NV does bring some order back to deal with VNCR-backed
registers).
[...]
diff --git a/arch/arm64/kvm/hyp/include/hyp/sysreg-sr.h
b/arch/arm64/kvm/hyp/include/hyp/sysreg-sr.h
index cce43bfe158f..94d9736f0133 100644
--- a/arch/arm64/kvm/hyp/include/hyp/sysreg-sr.h
+++ b/arch/arm64/kvm/hyp/include/hyp/sysreg-sr.h
@@ -45,6 +45,8 @@ static inline void __sysreg_save_el1_state(struct
kvm_cpu_context *ctxt)
ctxt_sys_reg(ctxt, CNTKCTL_EL1) =
read_sysreg_el1(SYS_CNTKCTL);
ctxt_sys_reg(ctxt, PAR_EL1) = read_sysreg_par();
ctxt_sys_reg(ctxt, TPIDR_EL1) = read_sysreg(tpidr_el1);
+ if (system_supports_mte())
+ ctxt_sys_reg(ctxt, TFSR_EL1) = read_sysreg_el1(SYS_TFSR);
I already asked for it, and I'm going to ask for it again:
Most of the sysreg save/restore is guarded by a per-vcpu check
(HCR_EL2.ATA), while this one is unconditionally saved/restore
if the host is MTE capable. Why is that so?
Sorry, I thought your concern was for registers that affect the host
(as they are obviously more performance critical as they are hit on
every guest exit). Although I guess that's incorrect for nVHE which is
what all the cool kids want now ;)
I think we want both correctness *and* performance, for both VHE
and nVHE. Things like EL0 registers should be able to be moved
to load/put on all implementations, and the correct switching
be done at the right spot only when required.
Thanks,
M.
--
Jazz is not dead. It just smells funny...
Re: [PATCH v7 1/3] arm64: kvm: Save/restore MTE registers
On 02/02/2021 15:36, Marc Zyngier wrote:
On 2021-01-15 15:28, Steven Price wrote:
Define the new system registers that MTE introduces and context switch
them. The MTE feature is still hidden from the ID register as it isn't
supported in a VM yet.
Signed-off-by: Steven Price
---
arch/arm64/include/asm/kvm_host.h | 4 ++
arch/arm64/include/asm/kvm_mte.h | 74 ++
arch/arm64/include/asm/sysreg.h | 3 +-
arch/arm64/kernel/asm-offsets.c | 3 +
arch/arm64/kvm/hyp/entry.S | 7 ++
arch/arm64/kvm/hyp/include/hyp/sysreg-sr.h | 4 ++
arch/arm64/kvm/sys_regs.c | 14 ++--
7 files changed, 104 insertions(+), 5 deletions(-)
create mode 100644 arch/arm64/include/asm/kvm_mte.h
diff --git a/arch/arm64/include/asm/kvm_host.h
b/arch/arm64/include/asm/kvm_host.h
index 11beda85ee7e..51590a397e4b 100644
--- a/arch/arm64/include/asm/kvm_host.h
+++ b/arch/arm64/include/asm/kvm_host.h
@@ -148,6 +148,8 @@ enum vcpu_sysreg {
SCTLR_EL1, /* System Control Register */
ACTLR_EL1, /* Auxiliary Control Register */
CPACR_EL1, /* Coprocessor Access Control */
+ RGSR_EL1, /* Random Allocation Tag Seed Register */
+ GCR_EL1, /* Tag Control Register */
ZCR_EL1, /* SVE Control */
TTBR0_EL1, /* Translation Table Base Register 0 */
TTBR1_EL1, /* Translation Table Base Register 1 */
@@ -164,6 +166,8 @@ enum vcpu_sysreg {
TPIDR_EL1, /* Thread ID, Privileged */
AMAIR_EL1, /* Aux Memory Attribute Indirection Register */
CNTKCTL_EL1, /* Timer Control Register (EL1) */
+ TFSRE0_EL1, /* Tag Fault Status Register (EL0) */
+ TFSR_EL1, /* Tag Fault Stauts Register (EL1) */
s/Stauts/Status/
Is there any reason why the MTE registers aren't grouped together?
I has been under the impression this list is sorted by the encoding of
the system registers, although double checking I've screwed up the order
of TFSRE0_EL1/TFSR_EL1, and not all the other fields are sorted that way.
I'll move them together in their own section.
PAR_EL1, /* Physical Address Register */
MDSCR_EL1, /* Monitor Debug System Control Register */
MDCCINT_EL1, /* Monitor Debug Comms Channel Interrupt Enable
Reg */
diff --git a/arch/arm64/include/asm/kvm_mte.h
b/arch/arm64/include/asm/kvm_mte.h
new file mode 100644
index ..62bbfae77f33
--- /dev/null
+++ b/arch/arm64/include/asm/kvm_mte.h
@@ -0,0 +1,74 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (C) 2020 ARM Ltd.
+ */
+#ifndef __ASM_KVM_MTE_H
+#define __ASM_KVM_MTE_H
+
+#ifdef __ASSEMBLY__
+
+#include
+
+#ifdef CONFIG_ARM64_MTE
+
+.macro mte_switch_to_guest g_ctxt, h_ctxt, reg1
+alternative_if_not ARM64_MTE
+ b .L__skip_switch\@
+alternative_else_nop_endif
+ mrs \reg1, hcr_el2
+ and \reg1, \reg1, #(HCR_ATA)
+ cbz \reg1, .L__skip_switch\@
+
+ mrs_s \reg1, SYS_RGSR_EL1
+ str \reg1, [\h_ctxt, #CPU_RGSR_EL1]
+ mrs_s \reg1, SYS_GCR_EL1
+ str \reg1, [\h_ctxt, #CPU_GCR_EL1]
+ mrs_s \reg1, SYS_TFSRE0_EL1
+ str \reg1, [\h_ctxt, #CPU_TFSRE0_EL1]
+
+ ldr \reg1, [\g_ctxt, #CPU_RGSR_EL1]
+ msr_s SYS_RGSR_EL1, \reg1
+ ldr \reg1, [\g_ctxt, #CPU_GCR_EL1]
+ msr_s SYS_GCR_EL1, \reg1
+ ldr \reg1, [\g_ctxt, #CPU_TFSRE0_EL1]
+ msr_s SYS_TFSRE0_EL1, \reg1
+
+.L__skip_switch\@:
+.endm
+
+.macro mte_switch_to_hyp g_ctxt, h_ctxt, reg1
+alternative_if_not ARM64_MTE
+ b .L__skip_switch\@
+alternative_else_nop_endif
+ mrs \reg1, hcr_el2
+ and \reg1, \reg1, #(HCR_ATA)
+ cbz \reg1, .L__skip_switch\@
+
+ mrs_s \reg1, SYS_RGSR_EL1
+ str \reg1, [\g_ctxt, #CPU_RGSR_EL1]
+ mrs_s \reg1, SYS_GCR_EL1
+ str \reg1, [\g_ctxt, #CPU_GCR_EL1]
+ mrs_s \reg1, SYS_TFSRE0_EL1
+ str \reg1, [\g_ctxt, #CPU_TFSRE0_EL1]
Can't the EL0 state save/restore be moved to the C code?
True, that should be safe. I'm not sure how I missed that.
+
+ ldr \reg1, [\h_ctxt, #CPU_RGSR_EL1]
+ msr_s SYS_RGSR_EL1, \reg1
+ ldr \reg1, [\h_ctxt, #CPU_GCR_EL1]
+ msr_s SYS_GCR_EL1, \reg1
+ ldr \reg1, [\h_ctxt, #CPU_TFSRE0_EL1]
+ msr_s SYS_TFSRE0_EL1, \reg1
+
+.L__skip_switch\@:
+.endm
+
+#else /* CONFIG_ARM64_MTE */
+
+.macro mte_switch_to_guest g_ctxt, h_ctxt, reg1
+.endm
+
+.macro mte_switch_to_hyp g_ctxt, h_ctxt, reg1
+.endm
+
+#endif /* CONFIG_ARM64_MTE */
+#endif /* __ASSEMBLY__ */
+#endif /* __ASM_KVM_MTE_H */
diff --git a/arch/arm64/include/asm/sysreg.h
b/arch/arm64/include/asm/sysreg.h
index 8b5e7e5c3cc8..0a01975d331d 100644
--- a/arch/arm64/include/asm/sysreg.h
+++ b/arch/arm64/include/asm/sysreg.h
@@ -574,7 +574,8 @@
#define SCTLR_ELx_M (BIT(0))
#define SCTLR_ELx_FLAGS (SCTLR_ELx_M | SCTLR_ELx_A | SCTLR_ELx_C | \
- SCTLR_ELx_SA | SCTLR_ELx_I | SCTLR_ELx_IESB)
+ SCTLR_ELx_SA | SCTLR_ELx_I | SCTLR_ELx_IESB | \
+
Re: [PATCH v7 1/3] arm64: kvm: Save/restore MTE registers
On 2021-01-15 15:28, Steven Price wrote:
Define the new system registers that MTE introduces and context switch
them. The MTE feature is still hidden from the ID register as it isn't
supported in a VM yet.
Signed-off-by: Steven Price
---
arch/arm64/include/asm/kvm_host.h | 4 ++
arch/arm64/include/asm/kvm_mte.h | 74 ++
arch/arm64/include/asm/sysreg.h| 3 +-
arch/arm64/kernel/asm-offsets.c| 3 +
arch/arm64/kvm/hyp/entry.S | 7 ++
arch/arm64/kvm/hyp/include/hyp/sysreg-sr.h | 4 ++
arch/arm64/kvm/sys_regs.c | 14 ++--
7 files changed, 104 insertions(+), 5 deletions(-)
create mode 100644 arch/arm64/include/asm/kvm_mte.h
diff --git a/arch/arm64/include/asm/kvm_host.h
b/arch/arm64/include/asm/kvm_host.h
index 11beda85ee7e..51590a397e4b 100644
--- a/arch/arm64/include/asm/kvm_host.h
+++ b/arch/arm64/include/asm/kvm_host.h
@@ -148,6 +148,8 @@ enum vcpu_sysreg {
SCTLR_EL1, /* System Control Register */
ACTLR_EL1, /* Auxiliary Control Register */
CPACR_EL1, /* Coprocessor Access Control */
+ RGSR_EL1, /* Random Allocation Tag Seed Register */
+ GCR_EL1,/* Tag Control Register */
ZCR_EL1,/* SVE Control */
TTBR0_EL1, /* Translation Table Base Register 0 */
TTBR1_EL1, /* Translation Table Base Register 1 */
@@ -164,6 +166,8 @@ enum vcpu_sysreg {
TPIDR_EL1, /* Thread ID, Privileged */
AMAIR_EL1, /* Aux Memory Attribute Indirection Register */
CNTKCTL_EL1,/* Timer Control Register (EL1) */
+ TFSRE0_EL1, /* Tag Fault Status Register (EL0) */
+ TFSR_EL1, /* Tag Fault Stauts Register (EL1) */
s/Stauts/Status/
Is there any reason why the MTE registers aren't grouped together?
PAR_EL1,/* Physical Address Register */
MDSCR_EL1, /* Monitor Debug System Control Register */
MDCCINT_EL1,/* Monitor Debug Comms Channel Interrupt Enable Reg */
diff --git a/arch/arm64/include/asm/kvm_mte.h
b/arch/arm64/include/asm/kvm_mte.h
new file mode 100644
index ..62bbfae77f33
--- /dev/null
+++ b/arch/arm64/include/asm/kvm_mte.h
@@ -0,0 +1,74 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (C) 2020 ARM Ltd.
+ */
+#ifndef __ASM_KVM_MTE_H
+#define __ASM_KVM_MTE_H
+
+#ifdef __ASSEMBLY__
+
+#include
+
+#ifdef CONFIG_ARM64_MTE
+
+.macro mte_switch_to_guest g_ctxt, h_ctxt, reg1
+alternative_if_not ARM64_MTE
+ b .L__skip_switch\@
+alternative_else_nop_endif
+ mrs \reg1, hcr_el2
+ and \reg1, \reg1, #(HCR_ATA)
+ cbz \reg1, .L__skip_switch\@
+
+ mrs_s \reg1, SYS_RGSR_EL1
+ str \reg1, [\h_ctxt, #CPU_RGSR_EL1]
+ mrs_s \reg1, SYS_GCR_EL1
+ str \reg1, [\h_ctxt, #CPU_GCR_EL1]
+ mrs_s \reg1, SYS_TFSRE0_EL1
+ str \reg1, [\h_ctxt, #CPU_TFSRE0_EL1]
+
+ ldr \reg1, [\g_ctxt, #CPU_RGSR_EL1]
+ msr_s SYS_RGSR_EL1, \reg1
+ ldr \reg1, [\g_ctxt, #CPU_GCR_EL1]
+ msr_s SYS_GCR_EL1, \reg1
+ ldr \reg1, [\g_ctxt, #CPU_TFSRE0_EL1]
+ msr_s SYS_TFSRE0_EL1, \reg1
+
+.L__skip_switch\@:
+.endm
+
+.macro mte_switch_to_hyp g_ctxt, h_ctxt, reg1
+alternative_if_not ARM64_MTE
+ b .L__skip_switch\@
+alternative_else_nop_endif
+ mrs \reg1, hcr_el2
+ and \reg1, \reg1, #(HCR_ATA)
+ cbz \reg1, .L__skip_switch\@
+
+ mrs_s \reg1, SYS_RGSR_EL1
+ str \reg1, [\g_ctxt, #CPU_RGSR_EL1]
+ mrs_s \reg1, SYS_GCR_EL1
+ str \reg1, [\g_ctxt, #CPU_GCR_EL1]
+ mrs_s \reg1, SYS_TFSRE0_EL1
+ str \reg1, [\g_ctxt, #CPU_TFSRE0_EL1]
Can't the EL0 state save/restore be moved to the C code?
+
+ ldr \reg1, [\h_ctxt, #CPU_RGSR_EL1]
+ msr_s SYS_RGSR_EL1, \reg1
+ ldr \reg1, [\h_ctxt, #CPU_GCR_EL1]
+ msr_s SYS_GCR_EL1, \reg1
+ ldr \reg1, [\h_ctxt, #CPU_TFSRE0_EL1]
+ msr_s SYS_TFSRE0_EL1, \reg1
+
+.L__skip_switch\@:
+.endm
+
+#else /* CONFIG_ARM64_MTE */
+
+.macro mte_switch_to_guest g_ctxt, h_ctxt, reg1
+.endm
+
+.macro mte_switch_to_hyp g_ctxt, h_ctxt, reg1
+.endm
+
+#endif /* CONFIG_ARM64_MTE */
+#endif /* __ASSEMBLY__ */
+#endif /* __ASM_KVM_MTE_H */
diff --git a/arch/arm64/include/asm/sysreg.h
b/arch/arm64/include/asm/sysreg.h
index 8b5e7e5c3cc8..0a01975d331d 100644
--- a/arch/arm64/include/asm/sysreg.h
+++ b/arch/arm64/include/asm/sysreg.h
@@ -574,7 +574,8 @@
#define SCTLR_ELx_M(BIT(0))
#define SCTLR_ELx_FLAGS(SCTLR_ELx_M | SCTLR_ELx_A | SCTLR_ELx_C | \
-SCTLR_ELx_SA | SCTLR_ELx_I | SCTLR_ELx_IESB)
+SCTLR_ELx_SA | SCTLR_ELx_I | SCTLR_ELx_IESB | \
+SCTLR_ELx_ITFSB)
/* SCTLR_EL2 specific flags. */
#define SCTLR_EL2_RES1 ((BIT(4)) | (BIT(5)) | (BIT(11)) | (BIT(16))
| \
diff --git
