Commit 19bff88e authored by wchen's avatar wchen Committed by Anup Patel
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RISC-V: KVM: Redirect AMO load/store misaligned traps to guest 



The M-mode redirects an unhandled misaligned trap back
to S-mode when not delegating it to VS-mode(hedeleg).
However, KVM running in HS-mode terminates the VS-mode
software when back from M-mode.
The KVM should redirect the trap back to VS-mode, and
let VS-mode trap handler decide the next step.
Here is a way to handle misaligned traps in KVM,
not only directing them to VS-mode or terminate it.

Signed-off-by: default avatarwchen <waylingII@gmail.com>
Reviewed-by: default avatarAnup Patel <anup@brainfault.org>
Signed-off-by: default avatarAnup Patel <anup@brainfault.org>
parent 78329084

arch/riscv/include/asm/csr.h

+2 −0
Original line number Diff line number Diff line
@@ -82,7 +82,9 @@ 
#define EXC_INST_ACCESS		1

#define EXC_INST_ILLEGAL	2

#define EXC_BREAKPOINT		3

#define EXC_LOAD_MISALIGNED	4

#define EXC_LOAD_ACCESS		5

#define EXC_STORE_MISALIGNED	6

#define EXC_STORE_ACCESS	7

#define EXC_SYSCALL		8

#define EXC_HYPERVISOR_SYSCALL	9

arch/riscv/kvm/vcpu_exit.c

+2 −0
Original line number Diff line number Diff line
@@ -183,6 +183,8 @@ int kvm_riscv_vcpu_exit(struct kvm_vcpu *vcpu, struct kvm_run *run, 
	run->exit_reason = KVM_EXIT_UNKNOWN;

	switch (trap->scause) {

	case EXC_INST_ILLEGAL:

	case EXC_LOAD_MISALIGNED:

	case EXC_STORE_MISALIGNED:

		if (vcpu->arch.guest_context.hstatus & HSTATUS_SPV) {

			kvm_riscv_vcpu_trap_redirect(vcpu, trap);

			ret = 1;