Commit 6898a55c authored by Christoffer Dall's avatar Christoffer Dall Committed by Oliver Upton
Browse files

KVM: arm64: nv: Handle trapped ERET from virtual EL2 



When a guest hypervisor running virtual EL2 in EL1 executes an ERET
instruction, we will have set HCR_EL2.NV which traps ERET to EL2, so
that we can emulate the exception return in software.

Reviewed-by: default avatarRussell King (Oracle) <rmk+kernel@armlinux.org.uk>
Reviewed-by: default avatarAlexandru Elisei <alexandru.elisei@arm.com>
Signed-off-by: default avatarChristoffer Dall <christoffer.dall@arm.com>
Signed-off-by: default avatarMarc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20230209175820.1939006-12-maz@kernel.org


Signed-off-by: default avatarOliver Upton <oliver.upton@linux.dev>
parent 93c33702

arch/arm64/include/asm/esr.h

+4 −0
Original line number Diff line number Diff line
@@ -272,6 +272,10 @@ 
		(((e) & ESR_ELx_SYS64_ISS_OP2_MASK) >>		\

		 ESR_ELx_SYS64_ISS_OP2_SHIFT))



/* ISS field definitions for ERET/ERETAA/ERETAB trapping */

#define ESR_ELx_ERET_ISS_ERET		0x2

#define ESR_ELx_ERET_ISS_ERETA		0x1



/*

 * ISS field definitions for floating-point exception traps

 * (FP_EXC_32/FP_EXC_64).

arch/arm64/include/asm/kvm_arm.h

+1 −1
Original line number Diff line number Diff line
@@ -344,7 +344,7 @@ 
	ECN(SP_ALIGN), ECN(FP_EXC32), ECN(FP_EXC64), ECN(SERROR), \

	ECN(BREAKPT_LOW), ECN(BREAKPT_CUR), ECN(SOFTSTP_LOW), \

	ECN(SOFTSTP_CUR), ECN(WATCHPT_LOW), ECN(WATCHPT_CUR), \

	ECN(BKPT32), ECN(VECTOR32), ECN(BRK64)

	ECN(BKPT32), ECN(VECTOR32), ECN(BRK64), ECN(ERET)



#define CPACR_EL1_TTA		(1 << 28)

#define CPACR_EL1_DEFAULT	(CPACR_EL1_FPEN_EL0EN | CPACR_EL1_FPEN_EL1EN |\

arch/arm64/kvm/handle_exit.c

+10 −0
Original line number Diff line number Diff line
@@ -207,6 +207,15 @@ static int kvm_handle_ptrauth(struct kvm_vcpu *vcpu) 
	return 1;

}



static int kvm_handle_eret(struct kvm_vcpu *vcpu)

{

	if (kvm_vcpu_get_esr(vcpu) & ESR_ELx_ERET_ISS_ERET)

		return kvm_handle_ptrauth(vcpu);



	kvm_emulate_nested_eret(vcpu);

	return 1;

}



static exit_handle_fn arm_exit_handlers[] = {

	[0 ... ESR_ELx_EC_MAX]	= kvm_handle_unknown_ec,

	[ESR_ELx_EC_WFx]	= kvm_handle_wfx,
@@ -222,6 +231,7 @@ static exit_handle_fn arm_exit_handlers[] = { 
	[ESR_ELx_EC_SMC64]	= handle_smc,

	[ESR_ELx_EC_SYS64]	= kvm_handle_sys_reg,

	[ESR_ELx_EC_SVE]	= handle_sve,

	[ESR_ELx_EC_ERET]	= kvm_handle_eret,

	[ESR_ELx_EC_IABT_LOW]	= kvm_handle_guest_abort,

	[ESR_ELx_EC_DABT_LOW]	= kvm_handle_guest_abort,

	[ESR_ELx_EC_SOFTSTP_LOW]= kvm_handle_guest_debug,