Commit 8f57adac authored by Anup Patel's avatar Anup Patel Committed by Anup Patel
Browse files

RISC-V: KVM: Break down the __kvm_riscv_switch_to() into macros 



Break down the __kvm_riscv_switch_to() function into macros so that
these macros can be later re-used by SBI NACL extension based low-level
switch function.

Signed-off-by: default avatarAnup Patel <apatel@ventanamicro.com>
Reviewed-by: default avatarAtish Patra <atishp@rivosinc.com>
Link: https://lore.kernel.org/r/20241020194734.58686-5-apatel@ventanamicro.com


Signed-off-by: default avatarAnup Patel <anup@brainfault.org>
parent b922307a

arch/riscv/kvm/vcpu_switch.S

+40 −12
Original line number Diff line number Diff line
@@ -11,11 +11,7 @@ 
#include <asm/asm-offsets.h>

#include <asm/csr.h>



	.text

	.altmacro

	.option norelax



SYM_FUNC_START(__kvm_riscv_switch_to)

.macro SAVE_HOST_GPRS

	/* Save Host GPRs (except A0 and T0-T6) */

	REG_S	ra, (KVM_ARCH_HOST_RA)(a0)

	REG_S	sp, (KVM_ARCH_HOST_SP)(a0)
@@ -40,10 +36,12 @@ SYM_FUNC_START(__kvm_riscv_switch_to) 
	REG_S	s9, (KVM_ARCH_HOST_S9)(a0)

	REG_S	s10, (KVM_ARCH_HOST_S10)(a0)

	REG_S	s11, (KVM_ARCH_HOST_S11)(a0)

.endm



.macro SAVE_HOST_AND_RESTORE_GUEST_CSRS __resume_addr

	/* Load Guest CSR values */

	REG_L	t0, (KVM_ARCH_GUEST_SSTATUS)(a0)

	la	t1, .Lkvm_switch_return

	la	t1, \__resume_addr

	REG_L	t2, (KVM_ARCH_GUEST_SEPC)(a0)



	/* Save Host and Restore Guest SSTATUS */
@@ -62,7 +60,9 @@ SYM_FUNC_START(__kvm_riscv_switch_to) 
	REG_S	t0, (KVM_ARCH_HOST_SSTATUS)(a0)

	REG_S	t1, (KVM_ARCH_HOST_STVEC)(a0)

	REG_S	t3, (KVM_ARCH_HOST_SSCRATCH)(a0)

.endm



.macro RESTORE_GUEST_GPRS

	/* Restore Guest GPRs (except A0) */

	REG_L	ra, (KVM_ARCH_GUEST_RA)(a0)

	REG_L	sp, (KVM_ARCH_GUEST_SP)(a0)
@@ -97,13 +97,9 @@ SYM_FUNC_START(__kvm_riscv_switch_to) 


	/* Restore Guest A0 */

	REG_L	a0, (KVM_ARCH_GUEST_A0)(a0)

.endm



	/* Resume Guest */

	sret



	/* Back to Host */

	.align 2

.Lkvm_switch_return:

.macro SAVE_GUEST_GPRS

	/* Swap Guest A0 with SSCRATCH */

	csrrw	a0, CSR_SSCRATCH, a0
@@ -138,7 +134,9 @@ SYM_FUNC_START(__kvm_riscv_switch_to) 
	REG_S	t4, (KVM_ARCH_GUEST_T4)(a0)

	REG_S	t5, (KVM_ARCH_GUEST_T5)(a0)

	REG_S	t6, (KVM_ARCH_GUEST_T6)(a0)

.endm



.macro SAVE_GUEST_AND_RESTORE_HOST_CSRS

	/* Load Host CSR values */

	REG_L	t0, (KVM_ARCH_HOST_STVEC)(a0)

	REG_L	t1, (KVM_ARCH_HOST_SSCRATCH)(a0)
@@ -160,7 +158,9 @@ SYM_FUNC_START(__kvm_riscv_switch_to) 
	REG_S	t1, (KVM_ARCH_GUEST_A0)(a0)

	REG_S	t2, (KVM_ARCH_GUEST_SSTATUS)(a0)

	REG_S	t3, (KVM_ARCH_GUEST_SEPC)(a0)

.endm



.macro RESTORE_HOST_GPRS

	/* Restore Host GPRs (except A0 and T0-T6) */

	REG_L	ra, (KVM_ARCH_HOST_RA)(a0)

	REG_L	sp, (KVM_ARCH_HOST_SP)(a0)
@@ -185,6 +185,34 @@ SYM_FUNC_START(__kvm_riscv_switch_to) 
	REG_L	s9, (KVM_ARCH_HOST_S9)(a0)

	REG_L	s10, (KVM_ARCH_HOST_S10)(a0)

	REG_L	s11, (KVM_ARCH_HOST_S11)(a0)

.endm



	.text

	.altmacro

	.option norelax



	/*

	 * Parameters:

	 * A0 <= Pointer to struct kvm_vcpu_arch

	 */

SYM_FUNC_START(__kvm_riscv_switch_to)

	SAVE_HOST_GPRS



	SAVE_HOST_AND_RESTORE_GUEST_CSRS .Lkvm_switch_return



	RESTORE_GUEST_GPRS



	/* Resume Guest using SRET */

	sret



	/* Back to Host */

	.align 2

.Lkvm_switch_return:

	SAVE_GUEST_GPRS



	SAVE_GUEST_AND_RESTORE_HOST_CSRS



	RESTORE_HOST_GPRS



	/* Return to C code */

	ret