Commit b93c17c4 authored by David Brazdil's avatar David Brazdil Committed by Marc Zyngier
Browse files

KVM: arm64: Trap host SMCs in protected mode 



While protected KVM is installed, start trapping all host SMCs.
For now these are simply forwarded to EL3, except PSCI
CPU_ON/CPU_SUSPEND/SYSTEM_SUSPEND which are intercepted and the
hypervisor installed on newly booted cores.

Create new constant HCR_HOST_NVHE_PROTECTED_FLAGS with the new set of HCR
flags to use while the nVHE vector is installed when the kernel was
booted with the protected flag enabled. Switch back to the default HCR
flags when switching back to the stub vector.

Signed-off-by: default avatarDavid Brazdil <dbrazdil@google.com>
Signed-off-by: default avatarMarc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20201202184122.26046-26-dbrazdil@google.com
parent fa8c3d65

arch/arm64/include/asm/kvm_arm.h

+1 −0
Original line number Diff line number Diff line
@@ -80,6 +80,7 @@ 
			 HCR_FMO | HCR_IMO | HCR_PTW )

#define HCR_VIRT_EXCP_MASK (HCR_VSE | HCR_VI | HCR_VF)

#define HCR_HOST_NVHE_FLAGS (HCR_RW | HCR_API | HCR_APK | HCR_ATA)

#define HCR_HOST_NVHE_PROTECTED_FLAGS (HCR_HOST_NVHE_FLAGS | HCR_TSC)

#define HCR_HOST_VHE_FLAGS (HCR_RW | HCR_TGE | HCR_E2H)



/* TCR_EL2 Registers bits */

arch/arm64/kvm/hyp/nvhe/hyp-init.S

+10 −0
Original line number Diff line number Diff line
@@ -88,6 +88,11 @@ SYM_CODE_END(__kvm_hyp_init) 
 * x0: struct kvm_nvhe_init_params PA

 */

SYM_CODE_START_LOCAL(___kvm_hyp_init)

alternative_if ARM64_KVM_PROTECTED_MODE

	mov_q	x1, HCR_HOST_NVHE_PROTECTED_FLAGS

	msr	hcr_el2, x1

alternative_else_nop_endif



	ldr	x1, [x0, #NVHE_INIT_TPIDR_EL2]

	msr	tpidr_el2, x1
@@ -230,6 +235,11 @@ reset: 
	msr	sctlr_el2, x5

	isb



alternative_if ARM64_KVM_PROTECTED_MODE

	mov_q	x5, HCR_HOST_NVHE_FLAGS

	msr	hcr_el2, x5

alternative_else_nop_endif



	/* Install stub vectors */

	adr_l	x5, __hyp_stub_vectors

	msr	vbar_el2, x5

arch/arm64/kvm/hyp/nvhe/switch.c

+4 −1
Original line number Diff line number Diff line
@@ -96,6 +96,9 @@ static void __deactivate_traps(struct kvm_vcpu *vcpu) 
	mdcr_el2 |= MDCR_EL2_E2PB_MASK << MDCR_EL2_E2PB_SHIFT;



	write_sysreg(mdcr_el2, mdcr_el2);

	if (is_protected_kvm_enabled())

		write_sysreg(HCR_HOST_NVHE_PROTECTED_FLAGS, hcr_el2);

	else

		write_sysreg(HCR_HOST_NVHE_FLAGS, hcr_el2);

	write_sysreg(CPTR_EL2_DEFAULT, cptr_el2);

	write_sysreg(__kvm_hyp_host_vector, vbar_el2);

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