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SubjectRe: [PATCH v2] KVM: VMX: Fix rflags cache during vCPU reset
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On 20/11/2017 23:52, Wanpeng Li wrote:
> diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
> index b348920..131fa1c 100644
> --- a/arch/x86/kvm/vmx.c
> +++ b/arch/x86/kvm/vmx.c
> @@ -5590,6 +5590,7 @@ static void vmx_vcpu_reset(struct kvm_vcpu *vcpu, bool init_event)
> vmcs_write64(GUEST_IA32_DEBUGCTL, 0);
> }
>
> + kvm_set_rflags(vcpu, 2);
> vmcs_writel(GUEST_RFLAGS, 0x02);

I think the vmcs_writel can go, kvm_set_rflags ends up calling
vmx_set_rflags.

> kvm_rip_write(vcpu, 0xfff0);
>
>

Beautified testcase:

#include <unistd.h>
#include <sys/syscall.h>
#include <string.h>
#include <stdint.h>
#include <linux/kvm.h>
#include <fcntl.h>
#include <sys/ioctl.h>

long r[5];
int main()
{
struct kvm_debugregs dr = { 0 };

r[2] = open("/dev/kvm", O_RDONLY);
r[3] = ioctl(r[2], KVM_CREATE_VM, 0);
r[4] = ioctl(r[3], KVM_CREATE_VCPU, 7);
struct kvm_guest_debug debug = {
.control = 0xf0403,
.arch = {
.debugreg[6] = 0x2,
.debugreg[7] = 0x2
}
};
ioctl(r[4], KVM_SET_GUEST_DEBUG, &debug);
ioctl(r[4], KVM_RUN, 0);
}

No need to do anything, I'll handle this patch after -rc1.

Paolo

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