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

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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: Anup Patel <apatel@ventanamicro.com>
Reviewed-by: Atish Patra <atishp@rivosinc.com>
Link: https://lore.kernel.org/r/20241020194734.58686-5-apatel@ventanamicro.com
Signed-off-by: Anup Patel <anup@brainfault.org>
This commit is contained in:
Anup Patel
2024-10-21 01:17:25 +05:30
committed by Anup Patel
parent b922307a5f
commit 8f57adac39
1 changed files with 40 additions and 12 deletions
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52
arch/riscv/kvm/vcpu_switch.S
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@@ -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