[PATCH v1 6/6] KVM: VMX: Get PT state from xsave area to variables

Luwei Kang
2019-05-16T08:27:05Z

This patch get the Intel PT state from xsave area to
variables when PT is change from enabled to disabled.
Because PT state is saved/restored to/from xsave area
by XSAVES/XRSTORES instructions when Intel PT is enabled.
The KVM guest may read this MSRs when PT is disabled
but the real value is saved in xsave area not variables.

Signed-off-by: Luwei Kang <luwei.kang@intel.com>
---
arch/x86/kvm/vmx/vmx.c | 13 +++++++++++++
1 file changed, 13 insertions(+)

diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index d323e6b..d3e2569 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -1000,6 +1000,16 @@ static inline void pt_save_msr(struct pt_state *ctx, u32 addr_range)
rdmsrl(MSR_IA32_RTIT_ADDR0_A + i, ctx->rtit_addrx_ab[i]);
}

+static void pt_state_get(struct pt_state *ctx, struct fpu *fpu, u32 addr_range)
+{
+ char *buff = fpu->state.xsave.extended_state_area;
+
+ /* skip riti_ctl register */
+ memcpy(&ctx->rtit_output_base, buff + sizeof(u64),
+ sizeof(struct pt_state) - sizeof(u64) +
+ sizeof(u64) * addr_range * 2);
+}
+
static void pt_guest_enter(struct vcpu_vmx *vmx)
{
struct pt_desc *desc;
@@ -1040,6 +1050,9 @@ static void pt_guest_enter(struct vcpu_vmx *vmx)
pt_save_msr(desc->host_ctx, desc->addr_range);
pt_load_msr(desc->guest_ctx, desc->addr_range);
}
+ } else if (desc->pt_xsave && desc->guest_xs->initialized) {
+ pt_state_get(desc->guest_ctx, desc->guest_xs, desc->addr_range);
+ desc->guest_xs->initialized = 0;
}
}

--
1.8.3.1