KVM: arm64: Save/Restore guest DISR_EL1

If we deliver a virtual SError to the guest, the guest may defer it
with an ESB instruction. The guest reads the deferred value via DISR_EL1,
but the guests view of DISR_EL1 is re-mapped to VDISR_EL2 when HCR_EL2.AMO
is set.

Add the KVM code to save/restore VDISR_EL2, and make it accessible to
userspace as DISR_EL1.

Signed-off-by: James Morse <james.morse@arm.com>
Reviewed-by: Marc Zyngier <marc.zyngier@arm.com>
Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
index 3014b39b8fe204298a2b2af2cb5c86526ebaa0d1..84fcb2a896a145374ab03d30aa4c62c4d5abe64e 100644 (file)
--- a/arch/arm64/include/asm/kvm_host.h
+++ b/arch/arm64/include/asm/kvm_host.h
@@ -121,6 +121,7 @@ enum vcpu_sysreg {
        PAR_EL1,        /* Physical Address Register */
        MDSCR_EL1,      /* Monitor Debug System Control Register */
        MDCCINT_EL1,    /* Monitor Debug Comms Channel Interrupt Enable Reg */
+       DISR_EL1,       /* Deferred Interrupt Status Register */
 
        /* Performance Monitors Registers */
        PMCR_EL0,       /* Control Register */

diff --git a/arch/arm64/include/asm/sysreg.h b/arch/arm64/include/asm/sysreg.h
index 52cfdc216bcf9da381a78eb35d0233c431924ad2..53d99c0944b100f095487a8377d87aed946f30c4 100644 (file)
--- a/arch/arm64/include/asm/sysreg.h
+++ b/arch/arm64/include/asm/sysreg.h
@@ -358,6 +358,7 @@
 #define SYS_VSESR_EL2                  sys_reg(3, 4, 5, 2, 3)
 #define SYS_FPEXC32_EL2                        sys_reg(3, 4, 5, 3, 0)
 
+#define SYS_VDISR_EL2                  sys_reg(3, 4, 12, 1,  1)
 #define __SYS__AP0Rx_EL2(x)            sys_reg(3, 4, 12, 8, x)
 #define SYS_ICH_AP0R0_EL2              __SYS__AP0Rx_EL2(0)
 #define SYS_ICH_AP0R1_EL2              __SYS__AP0Rx_EL2(1)

diff --git a/arch/arm64/kvm/hyp/sysreg-sr.c b/arch/arm64/kvm/hyp/sysreg-sr.c
index c54cc2afb92b071d3c8afc3c1e8243638f5bbc5d..2c17afd2be96b8fe7774de732fbe1717d614da24 100644 (file)
--- a/arch/arm64/kvm/hyp/sysreg-sr.c
+++ b/arch/arm64/kvm/hyp/sysreg-sr.c
@@ -66,6 +66,9 @@ static void __hyp_text __sysreg_save_state(struct kvm_cpu_context *ctxt)
        ctxt->gp_regs.spsr[KVM_SPSR_EL1]= read_sysreg_el1(spsr);
        ctxt->gp_regs.regs.pc           = read_sysreg_el2(elr);
        ctxt->gp_regs.regs.pstate       = read_sysreg_el2(spsr);
+
+       if (cpus_have_const_cap(ARM64_HAS_RAS_EXTN))
+               ctxt->sys_regs[DISR_EL1] = read_sysreg_s(SYS_VDISR_EL2);
 }
 
 static hyp_alternate_select(__sysreg_call_save_host_state,
@@ -119,6 +122,9 @@ static void __hyp_text __sysreg_restore_state(struct kvm_cpu_context *ctxt)
        write_sysreg_el1(ctxt->gp_regs.spsr[KVM_SPSR_EL1],spsr);
        write_sysreg_el2(ctxt->gp_regs.regs.pc,         elr);
        write_sysreg_el2(ctxt->gp_regs.regs.pstate,     spsr);
+
+       if (cpus_have_const_cap(ARM64_HAS_RAS_EXTN))
+               write_sysreg_s(ctxt->sys_regs[DISR_EL1], SYS_VDISR_EL2);
 }
 
 static hyp_alternate_select(__sysreg_call_restore_host_state,

diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
index 1830ebc227d18d7c5ad06e8f1858bbe8f33fa53a..9edf4ac8a3207502a6618c56764f9fd06caaf571 100644 (file)
--- a/arch/arm64/kvm/sys_regs.c
+++ b/arch/arm64/kvm/sys_regs.c
@@ -1169,6 +1169,7 @@ static const struct sys_reg_desc sys_reg_descs[] = {
        { SYS_DESC(SYS_AMAIR_EL1), access_vm_reg, reset_amair_el1, AMAIR_EL1 },
 
        { SYS_DESC(SYS_VBAR_EL1), NULL, reset_val, VBAR_EL1, 0 },
+       { SYS_DESC(SYS_DISR_EL1), NULL, reset_val, DISR_EL1, 0 },
 
        { SYS_DESC(SYS_ICC_IAR0_EL1), write_to_read_only },
        { SYS_DESC(SYS_ICC_EOIR0_EL1), read_from_write_only },