Christoffer Dall <christoffer.dall@xxxxxxxxxx> writes: > On Tue, Nov 25, 2014 at 04:10:05PM +0000, Alex Bennée wrote: <snip> >> --- a/arch/arm64/kvm/hyp.S >> +++ b/arch/arm64/kvm/hyp.S >> @@ -18,6 +18,7 @@ >> #include <linux/linkage.h> >> #include <linux/kvm.h> >> >> +#include <uapi/asm/kvm.h> >> #include <asm/assembler.h> >> #include <asm/memory.h> >> #include <asm/asm-offsets.h> >> @@ -174,6 +175,7 @@ >> ldr x3, [x0, #GUEST_DEBUG] >> tbz x3, #KVM_GUESTDBG_ENABLE_SHIFT, 2f // No guest debug >> >> + // Both Step and HW BP/WP ops need to modify spsr_el2 and mdscr_el1 >> // x0 - preserved as VCPU ptr >> // x1 - spsr >> // x2 - mdscr >> @@ -191,6 +193,11 @@ >> eor x1, x1, #DBG_SPSR_SS >> eor x2, x2, #DBG_MDSCR_SS >> 1: >> + // If we are doing HW BP/WP - set MDSCR_EL1.KDE/MDE >> + tbz x3, #KVM_GUESTDBG_USE_HW_BP_SHIFT, 3f >> + orr x2, x2, #DBG_MDSCR_KDE >> + orr x2, x2, #DBG_MDSCR_MDE >> +3: >> msr spsr_el2, x1 >> msr mdscr_el1, x2 >> 2: >> @@ -815,6 +822,33 @@ __restore_debug: >> >> ret >> >> +/* Setup debug state for debug of guest */ >> +__setup_debug: >> + // x0: vcpu base address >> + // x3: ptr to guest registers passed to setup_debug_registers >> + // x5..x20/x26: trashed >> + >> + mrs x26, id_aa64dfr0_el1 >> + ubfx x24, x26, #12, #4 // Extract BRPs >> + ubfx x25, x26, #20, #4 // Extract WRPs >> + mov w26, #15 >> + sub w24, w26, w24 // How many BPs to skip >> + sub w25, w26, w25 // How many WPs to skip >> + >> + mov x4, x24 >> + add x3, x0, #GUEST_DEBUG_BCR >> + setup_debug_registers dbgbcr >> + add x3, x0, #GUEST_DEBUG_BVR >> + setup_debug_registers dbgbvr >> + >> + mov x4, x25 >> + add x3, x0, #GUEST_DEBUG_WCR >> + setup_debug_registers dbgwcr >> + add x3, x0, #GUEST_DEBUG_WVR >> + setup_debug_registers dbgwvr >> + >> + ret >> + >> __save_fpsimd: >> save_fpsimd >> ret >> @@ -861,6 +895,13 @@ ENTRY(__kvm_vcpu_run) >> bl __restore_sysregs >> bl __restore_fpsimd >> >> + // Now is the time to set-up the debug registers if we >> + // are debugging the guest >> + ldr x3, [x0, #GUEST_DEBUG] >> + tbz x3, #KVM_GUESTDBG_USE_HW_BP_SHIFT, 2f >> + bl __setup_debug >> + b 1f >> +2: >> skip_debug_state x3, 1f >> bl __restore_debug >> 1: >> @@ -881,6 +922,11 @@ __kvm_vcpu_return: >> bl __save_fpsimd >> bl __save_sysregs >> >> + // If we are debugging the guest don't save debug registers >> + // otherwise we'll be trashing are only good copy we have. >> + ldr x3, [x0, #GUEST_DEBUG] >> + tbnz x3, #KVM_GUESTDBG_USE_HW_BP_SHIFT, 1f >> + > > we're introducing an awful lot of conditionals in the assembly code with > these patches, can you re-consider if there's a cleaner abstraction that > allows us to deal with some of this stuff in C-code? See previous mail. It would be good but we need a place to do it before we enter hyp.S on a KVM_RUN ioctl. I'm open to suggestions. > > -Christoffer -- Alex Bennée -- To unsubscribe from this list: send the line "unsubscribe linux-doc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
