Commit 755db234 authored by Marc Zyngier's avatar Marc Zyngier
Browse files

KVM: arm64: Generate final CTR_EL0 value when running in Protected mode 



In protected mode, late CPUs are not allowed to boot (enforced by
the PSCI relay). We can thus specialise the read_ctr macro to
always return a pre-computed, sanitised value. Special care is
taken to prevent the use of this custome version outside of
the protected mode.

Reviewed-by: default avatarQuentin Perret <qperret@google.com>
Signed-off-by: default avatarMarc Zyngier <maz@kernel.org>
parent 90134ac9

arch/arm64/include/asm/assembler.h

+13 −0
Original line number Diff line number Diff line
@@ -15,6 +15,7 @@ 
#include <asm-generic/export.h>



#include <asm/asm-offsets.h>

#include <asm/asm-bug.h>

#include <asm/cpufeature.h>

#include <asm/cputype.h>

#include <asm/debug-monitors.h>
@@ -270,12 +271,24 @@ alternative_endif 
 * provide the system wide safe value from arm64_ftr_reg_ctrel0.sys_val

 */

	.macro	read_ctr, reg

#ifndef __KVM_NVHE_HYPERVISOR__

alternative_if_not ARM64_MISMATCHED_CACHE_TYPE

	mrs	\reg, ctr_el0			// read CTR

	nop

alternative_else

	ldr_l	\reg, arm64_ftr_reg_ctrel0 + ARM64_FTR_SYSVAL

alternative_endif

#else

alternative_if_not ARM64_KVM_PROTECTED_MODE

	ASM_BUG()

alternative_else_nop_endif

alternative_cb kvm_compute_final_ctr_el0

	movz	\reg, #0

	movk	\reg, #0, lsl #16

	movk	\reg, #0, lsl #32

	movk	\reg, #0, lsl #48

alternative_cb_end

#endif

	.endm

arch/arm64/kernel/image-vars.h

+1 −0
Original line number Diff line number Diff line
@@ -65,6 +65,7 @@ __efistub__ctype = _ctype; 
KVM_NVHE_ALIAS(kvm_patch_vector_branch);

KVM_NVHE_ALIAS(kvm_update_va_mask);

KVM_NVHE_ALIAS(kvm_get_kimage_voffset);

KVM_NVHE_ALIAS(kvm_compute_final_ctr_el0);



/* Global kernel state accessed by nVHE hyp code. */

KVM_NVHE_ALIAS(kvm_vgic_global_state);

arch/arm64/kvm/va_layout.c

+7 −0
Original line number Diff line number Diff line
@@ -288,3 +288,10 @@ void kvm_get_kimage_voffset(struct alt_instr *alt, 
{

	generate_mov_q(kimage_voffset, origptr, updptr, nr_inst);

}



void kvm_compute_final_ctr_el0(struct alt_instr *alt,

			       __le32 *origptr, __le32 *updptr, int nr_inst)

{

	generate_mov_q(read_sanitised_ftr_reg(SYS_CTR_EL0),

		       origptr, updptr, nr_inst);

}