Re: [PATCH v4 07/29] KVM: arm64: Save/restore POE registers
From: Joey Gouly <joey.gouly@arm.com>
Date: 2024-08-16 15:13:10
Also in:
kvmarm, linux-fsdevel, linux-mm, linuxppc-dev
On Fri, Aug 16, 2024 at 03:55:11PM +0100, Marc Zyngier wrote:
On Fri, 03 May 2024 14:01:25 +0100, Joey Gouly [off-list ref] wrote:quoted
Define the new system registers that POE introduces and context switch them. Signed-off-by: Joey Gouly <joey.gouly@arm.com> Cc: Marc Zyngier <maz@kernel.org> Cc: Oliver Upton <redacted> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Will Deacon <will@kernel.org> --- arch/arm64/include/asm/kvm_host.h | 4 +++ arch/arm64/include/asm/vncr_mapping.h | 1 + arch/arm64/kvm/hyp/include/hyp/sysreg-sr.h | 29 ++++++++++++++++++++++ arch/arm64/kvm/sys_regs.c | 8 ++++-- 4 files changed, 40 insertions(+), 2 deletions(-)diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h index 9e8a496fb284..28042da0befd 100644 --- a/arch/arm64/include/asm/kvm_host.h +++ b/arch/arm64/include/asm/kvm_host.h@@ -419,6 +419,8 @@ enum vcpu_sysreg { GCR_EL1, /* Tag Control Register */ TFSRE0_EL1, /* Tag Fault Status Register (EL0) */ + POR_EL0, /* Permission Overlay Register 0 (EL0) */ + /* 32bit specific registers. */ DACR32_EL2, /* Domain Access Control Register */ IFSR32_EL2, /* Instruction Fault Status Register */@@ -489,6 +491,8 @@ enum vcpu_sysreg { VNCR(PIR_EL1), /* Permission Indirection Register 1 (EL1) */ VNCR(PIRE0_EL1), /* Permission Indirection Register 0 (EL1) */ + VNCR(POR_EL1), /* Permission Overlay Register 1 (EL1) */ + VNCR(HFGRTR_EL2), VNCR(HFGWTR_EL2), VNCR(HFGITR_EL2),diff --git a/arch/arm64/include/asm/vncr_mapping.h b/arch/arm64/include/asm/vncr_mapping.h index df2c47c55972..06f8ec0906a6 100644 --- a/arch/arm64/include/asm/vncr_mapping.h +++ b/arch/arm64/include/asm/vncr_mapping.h@@ -52,6 +52,7 @@ #define VNCR_PIRE0_EL1 0x290 #define VNCR_PIRE0_EL2 0x298 #define VNCR_PIR_EL1 0x2A0 +#define VNCR_POR_EL1 0x2A8 #define VNCR_ICH_LR0_EL2 0x400 #define VNCR_ICH_LR1_EL2 0x408 #define VNCR_ICH_LR2_EL2 0x410diff --git a/arch/arm64/kvm/hyp/include/hyp/sysreg-sr.h b/arch/arm64/kvm/hyp/include/hyp/sysreg-sr.h index 4be6a7fa0070..1c9536557bae 100644 --- a/arch/arm64/kvm/hyp/include/hyp/sysreg-sr.h +++ b/arch/arm64/kvm/hyp/include/hyp/sysreg-sr.h@@ -16,9 +16,15 @@ #include <asm/kvm_hyp.h> #include <asm/kvm_mmu.h> +static inline bool ctxt_has_s1poe(struct kvm_cpu_context *ctxt); + static inline void __sysreg_save_common_state(struct kvm_cpu_context *ctxt) { ctxt_sys_reg(ctxt, MDSCR_EL1) = read_sysreg(mdscr_el1); + + // POR_EL0 can affect uaccess, so must be saved/restored early. + if (ctxt_has_s1poe(ctxt)) + ctxt_sys_reg(ctxt, POR_EL0) = read_sysreg_s(SYS_POR_EL0); } static inline void __sysreg_save_user_state(struct kvm_cpu_context *ctxt)@@ -55,6 +61,17 @@ static inline bool ctxt_has_s1pie(struct kvm_cpu_context *ctxt) return kvm_has_feat(kern_hyp_va(vcpu->kvm), ID_AA64MMFR3_EL1, S1PIE, IMP); } +static inline bool ctxt_has_s1poe(struct kvm_cpu_context *ctxt) +{ + struct kvm_vcpu *vcpu; + + if (!system_supports_poe()) + return false; + + vcpu = ctxt_to_vcpu(ctxt); + return kvm_has_feat(kern_hyp_va(vcpu->kvm), ID_AA64MMFR3_EL1, S1POE, IMP); +} + static inline void __sysreg_save_el1_state(struct kvm_cpu_context *ctxt) { ctxt_sys_reg(ctxt, SCTLR_EL1) = read_sysreg_el1(SYS_SCTLR);@@ -77,6 +94,10 @@ static inline void __sysreg_save_el1_state(struct kvm_cpu_context *ctxt) ctxt_sys_reg(ctxt, PIR_EL1) = read_sysreg_el1(SYS_PIR); ctxt_sys_reg(ctxt, PIRE0_EL1) = read_sysreg_el1(SYS_PIRE0); } + + if (ctxt_has_s1poe(ctxt)) + ctxt_sys_reg(ctxt, POR_EL1) = read_sysreg_el1(SYS_POR); + ctxt_sys_reg(ctxt, PAR_EL1) = read_sysreg_par(); ctxt_sys_reg(ctxt, TPIDR_EL1) = read_sysreg(tpidr_el1);@@ -107,6 +128,10 @@ static inline void __sysreg_save_el2_return_state(struct kvm_cpu_context *ctxt) static inline void __sysreg_restore_common_state(struct kvm_cpu_context *ctxt) { write_sysreg(ctxt_sys_reg(ctxt, MDSCR_EL1), mdscr_el1); + + // POR_EL0 can affect uaccess, so must be saved/restored early. + if (ctxt_has_s1poe(ctxt)) + write_sysreg_s(ctxt_sys_reg(ctxt, POR_EL0), SYS_POR_EL0); } static inline void __sysreg_restore_user_state(struct kvm_cpu_context *ctxt)@@ -153,6 +178,10 @@ static inline void __sysreg_restore_el1_state(struct kvm_cpu_context *ctxt) write_sysreg_el1(ctxt_sys_reg(ctxt, PIR_EL1), SYS_PIR); write_sysreg_el1(ctxt_sys_reg(ctxt, PIRE0_EL1), SYS_PIRE0); } + + if (ctxt_has_s1poe(ctxt)) + write_sysreg_el1(ctxt_sys_reg(ctxt, POR_EL1), SYS_POR); + write_sysreg(ctxt_sys_reg(ctxt, PAR_EL1), par_el1); write_sysreg(ctxt_sys_reg(ctxt, TPIDR_EL1), tpidr_el1);diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c index c9f4f387155f..be04fae35afb 100644 --- a/arch/arm64/kvm/sys_regs.c +++ b/arch/arm64/kvm/sys_regs.c@@ -2423,6 +2423,7 @@ static const struct sys_reg_desc sys_reg_descs[] = { { 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_POR_EL1), NULL, reset_unknown, POR_EL1 }, { SYS_DESC(SYS_AMAIR_EL1), access_vm_reg, reset_amair_el1, AMAIR_EL1 }, { SYS_DESC(SYS_LORSA_EL1), trap_loregion },@@ -2506,6 +2507,7 @@ static const struct sys_reg_desc sys_reg_descs[] = { .access = access_pmovs, .reg = PMOVSSET_EL0, .get_user = get_pmreg, .set_user = set_pmreg }, + { SYS_DESC(SYS_POR_EL0), NULL, reset_unknown, POR_EL0 }, { SYS_DESC(SYS_TPIDR_EL0), NULL, reset_unknown, TPIDR_EL0 }, { SYS_DESC(SYS_TPIDRRO_EL0), NULL, reset_unknown, TPIDRRO_EL0 }, { SYS_DESC(SYS_TPIDR2_EL0), undef_access },@@ -4057,8 +4059,6 @@ void kvm_init_sysreg(struct kvm_vcpu *vcpu) kvm->arch.fgu[HFGxTR_GROUP] = (HFGxTR_EL2_nAMAIR2_EL1 | HFGxTR_EL2_nMAIR2_EL1 | HFGxTR_EL2_nS2POR_EL1 | - HFGxTR_EL2_nPOR_EL1 | - HFGxTR_EL2_nPOR_EL0 | HFGxTR_EL2_nACCDATA_EL1 | HFGxTR_EL2_nSMPRI_EL1_MASK | HFGxTR_EL2_nTPIDR2_EL0_MASK);@@ -4093,6 +4093,10 @@ void kvm_init_sysreg(struct kvm_vcpu *vcpu) kvm->arch.fgu[HFGxTR_GROUP] |= (HFGxTR_EL2_nPIRE0_EL1 | HFGxTR_EL2_nPIR_EL1); + if (!kvm_has_feat(kvm, ID_AA64MMFR3_EL1, S1POE, IMP)) + kvm->arch.fgu[HFGxTR_GROUP] |= (HFGxTR_EL2_nPOR_EL1 | + HFGxTR_EL2_nPOR_EL0); +As Broonie pointed out in a separate thread, this cannot work, short of making ID_AA64MMFR3_EL1 writable. This can be done in a separate patch, but it needs doing as it otherwise breaks migration. Thanks, M.
Looks like it's wrong for PIE currently too, but your patch here fixes that: https://lore.kernel.org/kvmarm/20240813144738.2048302-11-maz@kernel.org/ (local) If I basically apply that patch, but only for POE, the conflict can be resolved later, or a rebase will fix it up, depending on what goes through first. Thanks, Joey