On 28/07/2016 21:05, Tamas K Lengyel wrote:
> Add support for getting/setting registers through vm_event on ARM.
> The set of registers can be expanded in the future to include other registers
> as well if necessary but for now it is limited to TTB/CR/R0/R1, PC and CPSR.
>
> Signed-off-by: Tamas K Lengyel <tamas.leng...@zentific.com>
> ---
> Cc: Stefano Stabellini <sstabell...@kernel.org>
> Cc: Julien Grall <julien.gr...@arm.com>
> Cc: Razvan Cojocaru <rcojoc...@bitdefender.com>
> Cc: Jan Beulich <jbeul...@suse.com>
> Cc: Andrew Cooper <andrew.coop...@citrix.com>
For the x86 and common bits, Reviewed-by: Andrew Cooper
<andrew.coop...@citrix.com>
However,
> +#include <xen/sched.h>
> +#include <asm/vm_event.h>
> +
> +void vm_event_fill_regs(vm_event_request_t *req)
> +{
> + const struct cpu_user_regs *regs = guest_cpu_user_regs();
> +
> + req->data.regs.arm.cpsr = regs->cpsr;
> + req->data.regs.arm.pc = regs->pc;
> + req->data.regs.arm.ttbcr = READ_SYSREG(TCR_EL1);
> + req->data.regs.arm.ttbr0 = READ_SYSREG64(TTBR0_EL1);
> + req->data.regs.arm.ttbr1 = READ_SYSREG64(TTBR1_EL1);
> +}
> +
> +void vm_event_set_registers(struct vcpu *v, vm_event_response_t *rsp)
> +{
> + struct cpu_user_regs *regs = guest_cpu_user_regs();
> +
> + regs->cpsr = rsp->data.regs.arm.cpsr;
> + regs->pc = rsp->data.regs.arm.pc;
> + v->arch.ttbcr = rsp->data.regs.arm.ttbcr;
> + v->arch.ttbr0 = rsp->data.regs.arm.ttbr0;
> + v->arch.ttbr1 = rsp->data.regs.arm.ttbr1;
Not knowing anything about ARM, but this looks like it is missing some
sanity/plausibility checks (to protect Xen against accidental clobbering
from the vm_event listener), and some WRITE_SYSREG() to reload the new
values (unless this is done unconditionally later, at which point you
should at least leave a comment here saying so).
~Andrew
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