| Message ID | 20250227180526.1204723-3-mark.rutland@arm.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | KVM: arm64: PSCI relay fixes | expand |
On Thu, Feb 27, 2025 at 06:05:26PM +0000, Mark Rutland wrote: > From: Ahmed Genidi <ahmed.genidi@arm.com> > > When KVM is in protected mode, host calls to PSCI are proxied via EL2, > and cold entries from CPU_ON, CPU_SUSPEND, and SYSTEM_SUSPEND bounce > through __kvm_hyp_init_cpu() at EL2 before entering the host kernel's > entry point at EL1. While __kvm_hyp_init_cpu() initializes SPSR_EL2 for > the exception return to EL1, it does not initialize SCTLR_EL1. > > Due to this, it's possible to enter EL1 with SCTLR_EL1 in an UNKNOWN > state. In practice this has been seen to result in kernel crashes after > CPU_ON as a result of SCTLR_EL1.M being 1 in violation of the initial > core configuration specified by PSCI. > > Fix this by initializing SCTLR_EL1 for cold entry to the host kernel. > As it's necessary to write to SCTLR_EL12 in VHE mode, this > initialization is moved into __kvm_host_psci_cpu_entry() where we can > use write_sysreg_el1(). > > The remnants of the '__init_el2_nvhe_prepare_eret' macro are folded into > its only caller, as this is clearer than having the macro. > > Fixes: cdf367192766ad11 ("KVM: arm64: Intercept host's CPU_ON SMCs") > Reported-by: Leo Yan <leo.yan@arm.com> > Signed-off-by: Ahmed Genidi <ahmed.genidi@arm.com> > [ Mark: clarify commit message, handle E2H, move to C, remove macro ] > Signed-off-by: Mark Rutland <mark.rutland@arm.com> Reviewed-by: Leo Yan <leo.yan@arm.com> > Cc: Ahmed Genidi <ahmed.genidi@arm.com> > Cc: Ben Horgan <ben.horgan@arm.com> > Cc: Catalin Marinas <catalin.marinas@arm.com> > Cc: Leo Yan <leo.yan@arm.com> > Cc: Marc Zyngier <maz@kernel.org> > Cc: Oliver Upton <oliver.upton@linux.dev> > Cc: Will Deacon <will@kernel.org> > --- > arch/arm64/include/asm/el2_setup.h | 5 ----- > arch/arm64/kernel/head.S | 3 ++- > arch/arm64/kvm/hyp/nvhe/hyp-init.S | 2 -- > arch/arm64/kvm/hyp/nvhe/psci-relay.c | 3 +++ > 4 files changed, 5 insertions(+), 8 deletions(-) > > diff --git a/arch/arm64/include/asm/el2_setup.h b/arch/arm64/include/asm/el2_setup.h > index bc8ebd55788ac..7774aec91027e 100644 > --- a/arch/arm64/include/asm/el2_setup.h > +++ b/arch/arm64/include/asm/el2_setup.h > @@ -270,11 +270,6 @@ > .Lskip_gcs_\@: > .endm > > -.macro __init_el2_nvhe_prepare_eret > - mov x0, #INIT_PSTATE_EL1 > - msr spsr_el2, x0 > -.endm > - > .macro __init_el2_mpam > /* Memory Partitioning And Monitoring: disable EL2 traps */ > mrs x1, id_aa64pfr0_el1 > diff --git a/arch/arm64/kernel/head.S b/arch/arm64/kernel/head.S > index 2d56459d6c94c..2ce73525de2c9 100644 > --- a/arch/arm64/kernel/head.S > +++ b/arch/arm64/kernel/head.S > @@ -322,7 +322,8 @@ SYM_INNER_LABEL(init_el2, SYM_L_LOCAL) > msr sctlr_el1, x1 > mov x2, xzr > 3: > - __init_el2_nvhe_prepare_eret > + mov x0, #INIT_PSTATE_EL1 > + msr spsr_el2, x0 > > mov w0, #BOOT_CPU_MODE_EL2 > orr x0, x0, x2 > diff --git a/arch/arm64/kvm/hyp/nvhe/hyp-init.S b/arch/arm64/kvm/hyp/nvhe/hyp-init.S > index 3fb5504a7d7fc..f8af11189572f 100644 > --- a/arch/arm64/kvm/hyp/nvhe/hyp-init.S > +++ b/arch/arm64/kvm/hyp/nvhe/hyp-init.S > @@ -214,8 +214,6 @@ SYM_CODE_START_LOCAL(__kvm_hyp_init_cpu) > > bl __kvm_init_el2_state > > - __init_el2_nvhe_prepare_eret > - > /* Enable MMU, set vectors and stack. */ > mov x0, x28 > bl ___kvm_hyp_init // Clobbers x0..x2 > diff --git a/arch/arm64/kvm/hyp/nvhe/psci-relay.c b/arch/arm64/kvm/hyp/nvhe/psci-relay.c > index 9c2ce1e0e99a5..c3e196fb8b18f 100644 > --- a/arch/arm64/kvm/hyp/nvhe/psci-relay.c > +++ b/arch/arm64/kvm/hyp/nvhe/psci-relay.c > @@ -218,6 +218,9 @@ asmlinkage void __noreturn __kvm_host_psci_cpu_entry(bool is_cpu_on) > if (is_cpu_on) > release_boot_args(boot_args); > > + write_sysreg_el1(INIT_SCTLR_EL1_MMU_OFF, SYS_SCTLR); > + write_sysreg(INIT_PSTATE_EL1, SPSR_EL2); > + > __host_enter(host_ctxt); > } > > -- > 2.30.2 >
diff --git a/arch/arm64/include/asm/el2_setup.h b/arch/arm64/include/asm/el2_setup.h index bc8ebd55788ac..7774aec91027e 100644 --- a/arch/arm64/include/asm/el2_setup.h +++ b/arch/arm64/include/asm/el2_setup.h @@ -270,11 +270,6 @@ .Lskip_gcs_\@: .endm -.macro __init_el2_nvhe_prepare_eret - mov x0, #INIT_PSTATE_EL1 - msr spsr_el2, x0 -.endm - .macro __init_el2_mpam /* Memory Partitioning And Monitoring: disable EL2 traps */ mrs x1, id_aa64pfr0_el1 diff --git a/arch/arm64/kernel/head.S b/arch/arm64/kernel/head.S index 2d56459d6c94c..2ce73525de2c9 100644 --- a/arch/arm64/kernel/head.S +++ b/arch/arm64/kernel/head.S @@ -322,7 +322,8 @@ SYM_INNER_LABEL(init_el2, SYM_L_LOCAL) msr sctlr_el1, x1 mov x2, xzr 3: - __init_el2_nvhe_prepare_eret + mov x0, #INIT_PSTATE_EL1 + msr spsr_el2, x0 mov w0, #BOOT_CPU_MODE_EL2 orr x0, x0, x2 diff --git a/arch/arm64/kvm/hyp/nvhe/hyp-init.S b/arch/arm64/kvm/hyp/nvhe/hyp-init.S index 3fb5504a7d7fc..f8af11189572f 100644 --- a/arch/arm64/kvm/hyp/nvhe/hyp-init.S +++ b/arch/arm64/kvm/hyp/nvhe/hyp-init.S @@ -214,8 +214,6 @@ SYM_CODE_START_LOCAL(__kvm_hyp_init_cpu) bl __kvm_init_el2_state - __init_el2_nvhe_prepare_eret - /* Enable MMU, set vectors and stack. */ mov x0, x28 bl ___kvm_hyp_init // Clobbers x0..x2 diff --git a/arch/arm64/kvm/hyp/nvhe/psci-relay.c b/arch/arm64/kvm/hyp/nvhe/psci-relay.c index 9c2ce1e0e99a5..c3e196fb8b18f 100644 --- a/arch/arm64/kvm/hyp/nvhe/psci-relay.c +++ b/arch/arm64/kvm/hyp/nvhe/psci-relay.c @@ -218,6 +218,9 @@ asmlinkage void __noreturn __kvm_host_psci_cpu_entry(bool is_cpu_on) if (is_cpu_on) release_boot_args(boot_args); + write_sysreg_el1(INIT_SCTLR_EL1_MMU_OFF, SYS_SCTLR); + write_sysreg(INIT_PSTATE_EL1, SPSR_EL2); + __host_enter(host_ctxt); }